University of Southern California Dissertations and Theses

Effects of nicotine abstinence on orienting, executive function, arousal and vigilance

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Effects of nicotine abstinence on orienting, executive function, arousal and vigilance

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EFFECTS OF NICOTINE ABSTINENCE ON ORIENTING,

EXECUTIVE FUNCTION, AROUSAL AND VIGILANCE.

by

Anthony Joseph Rissling

A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(PSYCHOLOGY)

May 2008

Copyright 2008 Anthony Joseph Rissling

ii
Acknowledgements
I would like to express my sincere gratitude to my mentor Dr. Michael
Dawson for his professional and personal support during my time in graduate school.
I have grown as a person as well as a student of cognitive psychophysiology due to
him. Without Dr. Dawson’s support I would not have entered or completed this
program of study. I would also like to thank Dr. Anne Schell for her support,
guidance and overall patience. Thanks to her I have gained much knowledge in the
field of statistics and cognitive psychophysiology. I am indebted to both Drs. Dawson
and Schell for sharing their knowledge and all their encouragement over the years.
I am greatly indebted to Dr. Keith Nuechterlein for sharing his vast
knowledge and his endless generosity both during this project as well as over the
years. I am thankful to my committee members Drs. John, McClure, and Walsh who
have provided advice and constructive criticism on this project.
I gratefully acknowledge the assistance of Dr. Bill Williams for his many
scoring programs that have made this project possible.
I would like to thank my Mom and Dad for their never ending love and
support especially over the past few years. To Blu whose love and friendship has
meant a great deal.
Finally, I am indebted to my wife and best friend Michelle, whose endless
love and support continues to fuel my ambition, my passion for knowledge and has
guided my growth as a person.

iii
Table of Contents

Acknowledgements ii

List of Tables v

List of Figures vi

Abstract viii

Chapter 1: Introduction and Overview 1

Chapter 2: Neural Network Attention Model 5

Chapter 3: Skin Conductance Orienting and Arousal 10

Chapter 4: Prepulse Inhibition 15

Chapter 5: Continuous Performance Tests 20

Chapter 6: Nicotine Withdrawal Syndrome 27

Chapter 7: Summary and Purpose of Experiments 31

Chapter 8: Experiment 1 33

Methods 39

Results 47

Discussion 63

Chapter 9: Experiment 2 69

Methods 75

Results 83

Discussion 93

Chapter 10: Predictability of autonomic arousal to behavioral performance 95

Methods 97

iv
Results 98

Discussion 102

Chapter 11: Methodological issues 104

Chapter 12: General Discussion 110

Appendix A: Informed Consent Smoker Group 127

Appendix B: Informed Consent Nonsmoker Group 131

Appendix C: Medication and Health History Form 134

Appendix D: Fagerstrom Tolerance Questionnaire 138

v
List of Tables

Table 1: Participant demographics for Experiment 1. 40

Table 2: Participant demographics for Experiment 2. 76

vi
List of Figures

Figure 1: Adapted Posner and associates attention model 9

Figure 2: Attention model adapted to the measurement of prepulse
Inhibition
19

Figure 3: Examples of clear and degraded stimuli 23

Figure 4: Attention model adapted to continuous performance tasks 25

Figure 5: Mean SCOR and SCDR magnitudes during the passive attention
phase across conditions
49

Figure 6: Proportion of SCOR and SCDR responses during the passive
attention phase
52

Figure 7: Mean target and nontarget SCOR magnitude during the active
attention phase
55

Figure 8: Mean baseline startle eyeblink magnitude during the active
attention phase
58

Figure 9: Mean startle eyeblink magnitude at the 60 ms lead interval
during the active attention phase
60

Figure 10: Mean startle eyeblink magnitude at the 120 ms lead interval
during the active attention phase
61

Figure 11: Mean overall d΄ during the DS-APT 84

Figure 12: Mean overall d΄ during the Z-CPT 85

Figure 13: Mean overall d΄ during the DS-CPT 89

Figure 14: Mean overall reaction time during the DS-APT 90

Figure 15: Mean overall reaction time during the Z-CPT 91

Figure 16: Mean overall reaction time during the DS-CPT 92

Figure 17: Mean number of NS-SCRs during the passive attention phase 99

vii
Figure 18: Mean overall SCL during the three CPTs for the smoker group 100

Figure 19: Mean overall SCL during the three CPTs for the nonsmoker
Group
101

viii
Abstract
Following the neural network model of attention proposed by Posner and associates
two experiments were conducted. Student smokers were tested following smoking
and overnight abstinence to measure the effects of smoking on the specific processes
of attention (orienting, executive function, alerting). A group of nonsmokers was
tested twice without nicotine manipulation. During Experiment 1 the two
psychophysiological indices of attention, skin conductance orienting response and
prepulse inhibition of the startle eyeblink reflex were employed to test the effects of
nicotine on the attentional processes of orienting and executive function. No effect of
smoking was evidenced compared to abstinence on the psychophysiological
measures. The results of Experiment 1 indicated smoking did not affect the processes
of orienting or executive function when measured by the two psychophysiological
indices. Nonsmoker responses did not differ between comparable tests following
continued abstinence. During Experiment 2 three continuous performance tasks were
employed that manipulated the burden on early visual processing and vigilance to test
the effects of nicotine on these functions. Abstinence among smokers produced
reliably lower vigilance performance compared to ad lib smoking on the two tasks
that presented degraded stimuli and burdened early visual processing. The results
indicate that smoking abstinence affects the attentional processes of orienting and
executive function during the early stages of stimulus processing. Performance of
nonsmokers did not differ between comparable tests following continued abstinence.
A test of the differential effect of smoking and abstinence on males and females did

ix
not result in any differences for any of the dependent variables during Experiment 1
or 2. The autonomic rate of responding and level did not predict behavioral
performance on the any of the three continuous performance tasks employed
following smoking or abstinence indicating arousal did not affect the three processes
of attention (orienting, executive function or alerting).

1
Chapter 1

Introduction and Overview

Prolonged cessation from nicotine intake by a habitual user of nicotine produces a
marked abstinence syndrome (Kenny & Markou, 2001) whose characteristics often
include disruption of attention, leading to impaired performance on a variety of tasks.
However, nicotine administration by smoking or other forms of nicotine delivery in
nicotine-dependent individuals reduces disruptions in attention and performance and may
improve them beyond the level of nonsmokers.
Continuous performance tests (CPTs) have been the primary type of task used to
investigate the effects of nicotine on sustained attention and vigilance. CPTs are a class
of rapidly paced, relatively brief vigilance tasks with discrete target and nontarget stimuli.
The common characteristics of most CPTs include: the presentation of a random or quasi
random sequence of visual stimuli, a fixed and rapid stimulus rate (e.g. one every 1-2
seconds), brief exposure times for the individual stimuli (usually 40-200 ms range),
designation of a certain stimulus or sequence of stimuli as the target, and a required
motor response (i.e. verbal response, button press to targets). Decline in performance
during CPTs has been reliably reported in smokers following nicotine abstinence when
compared to nicotine intake by smoking (Edwards, Wesnes, Warburton, & Gale, 1985;
Gilbert, Dibb, Plath, & Hiyane, 2000; Lawrence, Ross, & Stein, 2002; Wesnes &
Warburton, 1978, 1984b), nicotine patch, tablets or gum (Edwards et al., 1985; Mancuso,
Andres, Ansseau, & Tirelli, 1999; Parrott & Winder, 1989). However, the specific stages
or processes of attention that are affected by nicotine that account for the possible

2
improvement (following intake) or deficit (following abstinence) in performance are not
well understood.
The startle eyeblink response and the skin conductance orienting response are two
physiological responses whose amplitudes are modifiable in such a way as to allow for
the measurement of the effects of drug manipulation and specific to startle eyeblink, the
effects on early versus late attentional processes.
Following the attentional model of Posner and associates (Fan & Posner, 2004;
Posner, Rueda, & Kanske, 2007; Posner & Peterson, 1990), the purpose of the two
experiments described here was to investigate the specific attentional processes that are
affected by nicotine intake and continued nicotine abstinence in smokers compared to
nonsmokers.
The secondary goals of these studies were first, to determine whether the effects
of nicotine systematically vary between male and female smokers; and second, to
determine whether nicotine intake facilitates attentional processes in smokers to a level
beyond that of nonsmokers. A final goal was to determine whether the physiological
indices of attention measured in Experiment 1 are predictive of behavioral performance
measured in Experiment 2.
Two experiments will be reported in this paper. The first approached the primary
and secondary goals by employing two psychophysiological indices of attention, the
startle eyeblink reflex and the skin conductance orienting response, and two
psychophysiological measures of autonomic arousal, number of nonspecific skin
conductance responses and skin conductance level. The second experiment employed

3
three behavioral measures of attention, the Degraded Stimulus Alerted Performance Test
(DS-APT), the Degraded Stimulus Continuous Performance Test (DS-CPT), and the Zero
Continuous Performance Test (Z-CPT). To accomplish the final goal the physiological
and behavioral data from Experiment 1 and Experiment 2 were utilized.
Chapter 2 will present an introduction of the neural network attentional model
proposed by Posner and associates (Fan & Posner, 2004; Posner et al., 2007; Posner &
Peterson, 1990). Next the autonomic indices of the early stages of attention will be
introduced and explored in regard to the proposed attention model in Chapter 3. Chapter
4 will introduce prepulse inhibition and its measurement of the orienting and executive
function processes proposed by Posner and associates. Chapter 5 will introduce the
continuous performance tasks and their relevance to the attentional model. Chapter 6 will
conclude the introduction with a discussion of the nicotine withdrawal syndrome and the
brain areas involved. Chapter 7 will summarize the chapters 1-6 and the purpose of the
two experiments. Chapter 8 will describe the effects of nicotine intake and abstinence
studies on the physiological measures of skin conductance and PPI as well as the
methods, results and discussion of Experiment 1. Chapter 9 will summarize the effects of
nicotine intake and abstinence studies on behavioral measures of attention, as well as the
methods, results and discussion of Experiment 2. Chapter 10 will review the effects of
nicotine intake and abstinence on autonomic arousal as well as the methods, results and
discussion of the secondary analyses regarding the predictability of autonomic arousal on
behavioral performance. The methodological issues involved in nicotine and smoking
studies will be discussed in relation to the current two experiments will be covered in

4
Chapter 11. The overall discussion of the results to the neural network model will be
discussed in Chapter 12. The last section will include references cited within the text.

5
Chapter 2
Neural Network Attention Model
Historically, theories of attention and information processing first focused on the
concept that information is processed through a sequence of “steps” or “stages” in a
framework of sequential processing of stimuli. These operations were proposed to be
serial and hierarchically arranged to occur at progressively “higher” sites in the central
nervous system. Abnormalities or deficits of information processing were therefore
conceptualized as occurring at various stages (early or late), resulting in physiological or
behavioral evidence of dysregulation or dysfunction.
The previous “stage” models have been challenged by “integrationist” models that
rely on neural network theory, which proposes that neurons in multiple neurotransmitter
systems integrate attentional functions that are time-coordinated across multiple sites
(Fan & Posner, 2004; Posner et al., 2007; Posner & Peterson, 1990). Posner and
associates (Fan & Posner, 2004; Posner et al., 2007; Posner & Peterson, 1990) propose a
neural network model of attention that divides the attention system into three distinct
networks located in three anatomical areas of the brain that are independently responsible
for the three main attentional functions (see Figure 1). One involves a change of state and
is referred to as alerting. The other two, orienting and executive function, involve the
selection and deciphering of stimuli.
Alerting
Alerting is related to how one initiates and maintains an alert state. The
description of alerting is similar to that of arousal. As with alerting, arousal ranges from

6
sleep to frantic states and changes over the course of the day. Current research suggests
a number of neural modulators including the norepinephrine system that arises from the
midbrain nucleus locus coeruleus and includes the medial and lateral frontal cortex and
the posterior parietal areas to be involved (Witte & Marrocco, 1997).
In all tasks involving long periods of processing the role of changes of state may
be important. Alertness reflects the state of an organism for processing information and is
an important condition in all tasks. Posner and Peterson (1990) refer to the underlying
arousal system which can influence both the posterior attentional system (superior
parietal lobe, temporal parietal junction, and lateral pulvinar nucleus of the posterior
lateral thalamus, superior colliculus, and posterior parietal cortex) and the anterior
attentional system (the lateral prefrontal cortical regions and the anterior cingulate cortex)
and therefore orienting and executive function processes. Therefore, changes in alertness
may affect orienting, executive function or maintaining a vigilant state (readiness to
detect and decipher new stimuli). Activation of the alerting system may enhance the
orienting and executive attentional functions by increasing focus, allowing for the
inhibition of processing of further stimuli until processing of the original stimulus is
complete. Prolonged tasks requiring vigilance or sustained attention require increased
alerting/arousal, which is difficult to sustain over long periods of time. Therefore alerting
decreases may be expressed by decreased vigilance.
Orienting
Orienting refers to the selective focusing of perceptual resources on a stimulus.
Orienting or specifically exogenous orienting may be triggered by the sudden

7
introduction of a novel stimulus. As will be discussed in Chapter 4, orienting may be
indexed peripherally by the skin conductance orienting response (SCOR). The orienting
system for visual events has been associated with a posterior attentional system (Fan &
Posner, 2004; Posner et al., 2007; Posner & Peterson, 1990).
Executive Function
The anterior attentional system is involved in executive function and deals with
conflict among competing responses (e.g. target, nontarget) and is related to issues such
as the development of self regulation of thoughts, feelings and behavior (Rueda, Posner,
& Rothbart, 2004). Executive function is required in resolving conflict between
responses, in working memory tasks and in problem solving (Botvinick, Braver, Barch,
Carter, & Cohen, 2001). It is the executive function network that discriminates targets
from nontargets during attention tasks. The anterior attentional system involves the lateral
prefrontal cortical regions and the anterior cingulate cortex and is modulated by
dopamine (Benes, 2000).
Summary
Posner and associates (Fan & Posner, 2004; Posner et al., 2007; Posner &
Peterson, 1990) propose a neural network model of attention that divides the attention
system into three distinct networks located in three anatomical areas of the brain that are
independently responsible for the three main attentional functions, alerting, orienting and
executive function (Figure 1). Due to the importance of perceptual processing in
discriminating targets from nontargets and its influences on executive function, the model
in Figure 1 depicts perceptual processing as a sub-area of executive function. The current

8
two experiments were designed to investigate the specific attentional processes that are
affected by nicotine intake and nicotine abstinence in smokers compared to nonsmokers
based on the neural network model and therefore will be discussed in terms of the model.

9
Figure 1: Adapted Posner and associates attention model

10
Chapter 3
Skin Conductance Orienting and Arousal
Orienting is a generalized response to unexpected, novel or salient stimuli. It
prepares the individual to detect and act quickly to an unexpected event. The passive
orienting response (OR) directs our attention to novel stimuli and enhances sensory
processing. It was first described by Pavlov as the investigatory or ‘what-is-it?’ reflex
(Pavlov, 1927). According to Sokolov (1960) the OR is “the first response of the body to
any type of stimulus” and its function is “to ensure optimal perception of the stimulus
(p.11)”. The most convenient index of the OR is the skin conductance response, referred
to as the skin conductance orienting response (SCOR).
Öhman (1992; 1993), suggests that biologically prepared stimuli (e.g. snakes and
spiders) are preattentively processed, resulting in an SCOR which is evidence of the call
for the allocation of processing resources, while neutral stimuli presented passively result
in an SCOR which is result of the allocation of processing resources.
According to information processing theory the SCOR is evidence of the
allocation of processing resources to a stimulus and is determined by a limited resource
central processing mechanism (Kahneman, 1973).The allocation of processing resources
implies that attentional resources are allocated to the orienting task and therefore fewer
resources are available to be allocated to other, simultaneous tasks.
As with many physiological responses, the SCOR may be modulated by salience
of the stimuli during active attention tasks. Therefore, the OR may be influenced by top
down attentional modulation in instances when a stimulus is given greater salience over

11
others. Dawson, Filion and Schell (1989) and Filion, Dawson, Schell, and Hazlett
(1991), measured SCORs and secondary reaction time to task relevant and task irrelevant
tones and reported larger SCORs to task relevant than task irrelevant tones. Further,
secondary reaction time was extended during the presence of a task relevant stimulus
relative to its absence and during a novel compared to during a familiar stimulus. The
results are consistent with the view that the SCOR is evidence of the allocation of
processing resources and may be modified by attentional top down control.
According to the neural network model proposed by Posner and associates,
orienting involves selective focusing of perceptual resources on a stimulus. The SCOR
during passive tasks is a physiological index of this selective focusing of attention and
may index the amount of resources allocated. Further, the attentional top down
modulation suggests the executive function process may influence the SCOR response
during active attention tasks. Therefore, the SCOR may reflect the orienting and
executive function stages of the attentional model during detection and stimulus
processing of the stimuli. The attentional modulation of the SCOR reflects the executive
function stage where the relevance of the stimuli as target or nontarget is determined.
SC Defensive Responses
A defensive response is suggested to be similar to an orienting response with
some important differences. While the orienting response is elicited by novel or
significant neutral stimuli, the defensive response is elicited by high-intensity aversive
stimuli. It is associated with the suppression or inhibition of sensory input and does not
habituate to repeated presentations (Graham, 1992). As with the orienting response the

12
defensive response may be measured by skin conductance and is referred to as a skin
conductance defensive response (SCDR).
In relation to the neural network model the SCDR is related to the blocking out or
filtering of aversive stimuli during the orienting and executive function stages. Changes
in SCDR amplitude indicate a change in a subject’s ability to filter out aversive stimuli
during the orienting and executive function stages.
Arousal
Similar to the definition of alerting the definition of arousal refers to a general
physiological dimension that ranges from drowsiness to alertness and finally to frantic
activation levels. Autonomic arousal may be measured peripherally by the number of
non-specific skin conductance responses (NS-SCRs) that occur in the absence of a
stimulus or skin conductance level (SCL) measured as the average level over a given
period of time. Silverman, Cohen, and Shmavonian (1959) reported that the number of
NS-SCRs increases with increments of arousal while the magnitude of specific SCORs
increases up to a point but then decreases.
Level of arousal may be predictive of behavioral performance. Previous studies
measuring autonomic arousal as tonic skin conductance have reported an inverted U
relation between performance and arousal (Courts, 1942; Freeman, 1940; Pinneo, 1961).
Specifically, performance was optimal at moderate levels and is inferior at higher or
lower levels of activation.
Davies and Parasuraman (1982) reviewed six studies of the relationship between
electrodermal responding and vigilance performance and concluded that the results were

13
reasonably consistent. In every case where a vigilance decrement over time was
reported, individuals with low frequencies of electrodermal responses at rest and/or fast
SCOR habituation to neutral stimuli showed a greater decline than individuals with high
frequencies of NS-SCRs at rest and/or slow SCOR habituation to neutral stimuli.
Specific to the current study, Munro, Dawson, Schell, and Sakai (1987),
employing a degraded stimulus continuous performance task, reported that a rapid
vigilance decrement indexed by decreases in d΄ within 5-10 minutes occurred only in a
subgroup of subjects identified by their low rate of NS-SCRs (electrodermal stabiles).
They suggested that degrading the stimulus causes a specific subgroup of subjects to
become perceptually less sensitive to the visual target and that electrodermally labile
subjects (as compared to stabile subjects) are better able to mobilize and sustain their
attentional capacity, even for short periods of time, in high attentional demand situations.
Koelega (1990) in a review examined measures of speed of habituation of SCORs and
number of NS-SCRs, the electrodermal predictors previously used in vigilance studies,
and reported that subjects who’s SCORs habituated slowly display a high overall level of
performance, regardless of task demands and modality.
Although autonomic arousal measures have shown promise in predicting
behavioral performance during continuous performance tasks, the specific processes that
the autonomic measures are predicting are uncertain. According to the neural network
model of attention, the effects may be due to arousal’s influence on the processes of
orienting and/or executive function. One goal of the current experiments is to determine
for which type of continuous performance task(s) autonomic arousal measures are

14
predictive of performance and which sub-processes of attention autonomic arousal may
affect (orienting, executive function or vigilance).
Summary
Autonomic arousal may be measured peripherally by the number of NS-SCRs or
the skin conductance level. The studies cited indicate that measures of tonic or phasic
autonomic arousal have shown promise in predicting performance. Specific to CPT
performance, overall skin conductance responding measured as the number of NS-SCRs
has been reported to reliably predict performance when the task causes a decline in
vigilance.

15
Chapter 4
Prepulse Inhibition
An abrupt onset of a stimulus of sufficient intensity, such as a brief burst of white
noise, elicits a startle reflex response. In humans this response is most commonly
measured by the amplitude of the eyeblink (see Blumenthal et al., 2005 for a recent
review of startle elicitation, recording and quantification). Startle eyeblink is an
automatic reflexive response. However, the magnitude of the response is modified if the
startle eliciting stimulus is preceded by a non-startling stimulus. The magnitude of the
startle reflex can be reliably and predictably inhibited if the lead interval between the
onset of a preceding neutral lead stimulus (prepulse) and the startle eliciting stimulus is
relatively short (between 15-400 ms). This significant inhibition in blink magnitude is
termed prepulse inhibition (PPI) (see reviews by Blumenthal, 1999; Filion, Dawson, &
Schell, 1998). PPI is commonly viewed as a measure of “sensorimotor gating”, by which
excess or trivial stimuli are screened or “gated out” of awareness, so that attentional
resources may be selectively allocated to salient stimuli (Braff & Geyer, 1990; Granholm,
Perry, Filoteo, & Braff, 1999). PPI has been argued to “protect preattentive stimulus
processing allowing for finer stimulus analysis to proceed with minimal interruption
during the critical period needed for stimulus recognition” (Graham, 1980 p. 512).
PPI is influenced by both state and trait determinants. Thus, as discussed below,
PPI may be influenced by top down processing as well as by neurochemical changes in
the nervous system caused by drug intake or abstinence.

16
Attentional Modulation
During selective attention tasks short lead interval startle eyeblink modification is
modified by controlled attentional processes, with greater startle eyeblink inhibition
following an attended prepulse than an ignored prepulse (see review by Dawson, Schell,
Swerdlow, & Filion, 1997).
Several studies have shown greater PPI to attended lead stimuli than to ignored lead
stimuli (e.g. Dawson, Hazlett, Filion, & Nuechterlein, 1993; Filion, Dawson, & Schell,
1993; Hawk, Pelham, & Yartz, 2002; Jennings, Schell, Filion, & Dawson, 1996; Schell,
Dawson, Hazlett, & Filion, 1995). In all of these studies two different lead stimuli were
presented (e.g. high and low pitch tones), with the instruction to attend to one type and
ignore the other. Acoustic startle was elicited at short lead intervals (typically at 60, 120
and 240 ms after onset of the continuous tones). The consistent pattern of results obtained
in these studies showed enhanced PPI of the startle eyeblink response during attended
tones compared with ignored tones at a lead interval of 120 ms. Attentional modulation
of PPI was not seen at earlier (60 ms) or later (240 ms) lead intervals. The evidence
suggests that top down modulated attentional processes develop more slowly than the
more automatic processes. That is, PPI at the 60 ms lead interval is hypothesized to probe
automatic processes whereas the 120 ms lead interval probes top down attentional
processes. The absence of modulation at 240 ms indicates that during the auditory task
the early processing stage is complete by 240 ms.

17
Relevance to Attention Model
The measurement of the startle eyeblink reflex and specifically PPI may be
employed as a powerful tool to index the early processes of attention. Figure 2 is a
schematic of how the different lead intervals coincide with the separate attentional
functions of the neural network model proposed by Posner and associates.
Presentation of a pre-stimulus or prepulse (e. g. tone) activates the orienting
system. The alerting/arousal system is activated and focuses the early stage of attention.
This increased focus allows for the inhibition of immediately following stimuli until
initial processing is complete. Therefore, the prepulse elicits an increase in alertness that
is sustained throughout the orienting and executive function processes. Startle stimuli
delivered with a 60 ms lead interval probe the orienting process during stimulus
detection, which does not evidence top down attentional modulation. Startle stimuli at the
120 ms lead interval probe the discrimination between stimuli and decision regarding task
relevance during the executive function process, which is evidenced by the attentional
modulation of the startle response (smaller startle amplitude to target than nontarget
stimuli).
Summary
The measurement of the startle eyeblink reflex and specifically PPI may be
employed as a powerful tool to index the orienting and executive function processes of
attention. In a passive attention paradigm without demands to actively engage attentional
mechanisms, startle eyeblink modification may index automatic sensorimotor gating
processes at short lead intervals (orienting process). During selective attention tasks short

18
lead interval startle eyeblink modification is modified by controlled attentional
processes with greater inhibition following an attended prepulse than an ignored prepulse
(executive function process). PPI at the 60 ms lead interval is suggested to probe
automatic processes (orienting) while the 120 ms lead interval probes controlled
attentional modulation of PPI (executive function).

19

Figure 2: Attention model adapted to prepulse inhibition.

20
Chapter 5
Continuous Performance Tests
Vigilance has been defined as “a state of readiness to detect and respond to certain
small changes occurring at random time intervals in the environment” (Mackworth, 1969,
pp. 389-390). In the context of a continuous performance test (CPT), vigilance level
refers to the overall level of detection performance averaged over the entire vigilance
period. Vigilance decrement refers to the decline in the vigilant state over time evidenced
by the decreasing accuracy of signal detection over time during the task.
Performance Measurement
Measurement of performance on CPTs may be accomplished in several ways
depending on the type of task employed. A common approach is to measure the number
of correct target detections (hits), number of incorrect responses (misses) or the number
of false alarms (responses to nontarget stimuli) to evaluate overall vigilance performance
and vigilance decrement. However, the use of signal detection indices (e.g. d΄, β), which
are derived from the traditional error scores (hit rate, false alarm rate); offers an
advantage of more clearly differentiating the underlying processes believed to account for
vigilance performance (Nuechterlein, 1991).
Sensitivity refers to the individual’s ability to discriminate the target stimuli from
nontarget stimuli. An individual with high sensitivity typically has a high hit rate (few
errors of omission) and a relatively low false alarm rate (few errors of commission). The
most common index of sensitivity is d-prime (d΄). This index assumes that the
distributions of signal response probability for present and noise trials are normal and

21
have equal variance. Overall sensitivity is measured as d΄ calculated as the standardized
difference between the means of the signal and noise distributions. The formula is d΄= z
(H) – z (FA) where z (H) and z (FA) represent the transformation of the hit and false
alarm rates to z-scores. d' represents the distance between the means of the signal and
noise distributions in standard deviation units. Larger absolute values of d' mean that a
person is more sensitive to the difference between the signal and noise conditions. d'
values near zero indicate chance performance (Aberson, Berger, Emerson, & Romero,
1997).
Response criterion refers to the amount of perceptual evidence that the person
requires to indicate that the stimulus is a signal and is referred to as β. This is calculated
as the ratio of the individual’s ordinate on the hit rate distribution (y (hit rate)), to that of
the ordinate on the false alarm rate distribution (y (false alarm rate)). For example an
individual with a high response criterion typically has a low target hit rate and a very low
false alarm rate. However, a person using a low response criterion has a relatively higher
hit rate, but also a higher false alarm rate (Aberson et al., 1997).
According to Aberson et al. (1997) the logic of the signal detection theory model
is very similar to statistical hypothesis testing. The noise distribution corresponds to the
null hypothesis distribution, the signal distribution is the alternative distribution, and the
response criterion is the alpha error rate. The advantage of employing these signal
detection indices over the earlier method of hit rate and false alarm rate is that a focus on
hit rate alone cannot distinguish between those who are unable to discriminate the target
and nontarget stimuli from those individuals who use a cautious response criterion.

22
Similarly identification of those having a high false alarm rate cannot distinguish
between individuals who are unable to discriminate the nontargets from the target stimuli
and those who use a low response criterion and respond impulsively to the nontarget
trials.
Response or reaction time (RT) is often employed as a secondary measure. RT is
argued to be a measure of processing speed. Effects reported on RT may be due to effects
on motor response speed.
The Degraded Stimulus Continuous Performance Task (DS-CPT), which is a
simultaneous discrimination (the signal can be discriminated based on elements that are
present at the same time or within the same stimulus event), vigilance task that involves
very subtle perceptual discriminations due to the blurring of stimuli (Nuechterlein, 1983;
see Figure 3 for example of stimuli). The degrading of the stimuli in the DS-CPT requires
greater and more sustained allocation of attention resources due to the increased burden
on perceptual analysis (Nuechterlein, 1983; Rissling, Dawson, Schell, & Nuechterlein,
2005) compared to the relatively easy recognition that characterizes clearly discriminable
stimuli in most simultaneous discrimination vigilance tasks. The increased attention
demands are evidenced by a greater vigilance decrement over short periods of time
(Nuechterlein, 1983) and decreased processing speed measured as reaction time (Rissling
et al., 2005).

23

Figure 3: Examples of clear and degraded stimuli.

24
Relevance to Attention Model
The process of performing a CPT involves three attentional components: orienting
to sensory events, identifying and discriminating signals (executive function) and
maintaining a vigilant or alert state. As the subject watches the computer screen he/she
must first orient to the visual stimulus. The subject must first detect the signal and then
make a decision regarding whether it is a target or non-target, which requires perceptual
processing. If the subject decides the stimulus is a target a motor response is initiated.
The speed of the motor response may be an indicator of the speed of processing of the
stimuli. The third component involves maintaining an alert and vigilant state in
preparation for the presentation of the next stimulus. Effects on any of the three functions
may be evidenced by a decrease in overall sensitivity level as measured by d΄.
Figure 4 is a schematic that indicates the order of each attention process that
sequentially occurs during the timing of the CPT. The process of orienting and executive
function follow the presentation of the CPT stimuli (digit). The effect of the third process,
alerting/arousal may, be manifest in orienting, executive function or in maintaining a
vigilant state, as indicated. Burden placed on any of these stages may affect the
autonomic arousal level of the subject.
When the stimuli are degraded, as in the DS-CPT, the burden is on early
perceptual processing involving the discrimination of the digits and on the executive
function process. The rapid pace of a CPT further requires a high level of alerting and the
subject’s ability to maintain vigilance, which may be evidenced peripherally by increases
in autonomic arousal.

25
Figure 4: Attention Model Adapted to Continuous Performance Tasks

26
Summary
Continuous performance tests (CPTs) have been a primary type of task used to
measure vigilance. Measurement of performance may be accomplished in several ways
depending on the type of task employed. However, the use of signal detection indices
(e.g. d΄, β), which are derived from the traditional error scores (hit rate, false alarm rate);
offers an advantage of more clearly differentiating the underlying processes believed to
account for vigilance performance. Response or reaction time (RT) is often employed as
a secondary measure and is argued to be a measure of processing speed.
The process of performance during a CPT involves the three attentional
components proposed by Posner and associates: orienting to sensory events, identifying
and discriminating signals (executive function) and maintaining a vigilant or alert state.
Effects on any of the stages may be indexed by a drop in sensitivity measured by d΄.
Increased burden either by increased perceptual load or increased rate of the digits may
be evidenced by an increase in autonomic arousal.

27
Chapter 6
Nicotine Withdrawal Syndrome
When habitual cigarette smokers abstain from smoking, they frequently
experience a myriad of negative affective and cognitive symptoms. These symptoms
often include craving for cigarettes, restlessness, anger and irritability, anxiety, depressed
affect, difficulty concentrating, sleep disturbances and increased appetite (Gross &
Stitzer, 1989; Hatsukami, Fletcher, Morgan, Keenan, & Amble, 1989; Hughes, Gust,
Skoog, Keenan, & Fenwick, 1991; Hughes & Hatsukami, 1986; West & Hack, 1991;
West, Hajek, & Belcher, 1989). Symptoms are intensified by abrupt abstinence from
nicotine, begin within a few hours, peak within a few days, and typically last for several
weeks, although considerable variability exists (Hughes, Higgins, & Hatsukami, 1990).
Nicotine intake has been reported to alleviate the number and intensity of withdrawal
symptoms (Hatsukami, Hughes, Pickens, & Svikis, 1984).
Although over two thousand different compounds have been identified in
cigarette smoke, nicotine is generally acknowledged as the substance accountable for
physiological (Benowitz, 1996) and cognitive (Heishman, Henningfield, & Singleton,
2002; Rezvani & Levin, 2001) changes following intake or abstinence. Therefore,
cognitive performance changes following nicotine intake or its abstinence will be the
focus of the current review.
Effects on the Central Nervous System
Nicotinic acetylcholine receptors (nAChRs) are a family of ligand gated ion
channels that mediate the effects of nicotine. Multiple subtypes of these receptors exist,

28
each with individual pharmacological and functional profiles (see Patterson &
Nordberg, 2000 for a review). They are expressed on mature skeletal muscle, in
autonomic ganglia and are widely distributed in the central nervous system (CNS)
(Holladay, Dart, & Lynch, 1997; Patterson & Nordberg, 2000). Their distribution in the
CNS has the highest density in the thalamus, caudate, and substantia nigra, and moderate
to low densities in the frontal, parietal, temporal and occipital cortex (Patterson &
Nordberg, 2000).
Nicotine initiates its activation by binding to nAChRs. The binding causes
desensitization of the nAChRs in the central nervous system. Due to the desensitization,
long-term exposure to nicotine or nicotine agonists causes an increase in the number of
nAChRs in the brains of humans, rats and mice (Marks et al., 1992; Perry, Davila-Garcia,
Stockmeier, & Kellar, 1999; Wonnacott, 1990). The increase is specific to nAChRs,
especially those with a high affinity for nicotine (Buisson & Bertrand, 2001). In the
desensitized conformations the nAChRs are turned over in the cell membrane more
slowly, leading to an overall increase in their number (Peng, Gerzanich, Anand, Wang, &
Lindstrom, 1997; Peng, Gerzanich, Anand, Whiting, & Lindstrom, 1994). When nicotine
levels are diminished in the brain the excess of nAChRs recover from desensitization,
resulting in an excess excitability of the nicotinic cholinergic systems. This excess may
lead to early symptoms of withdrawal (i.e. agitation, difficulty concentrating). Prolonged
cessation from nicotine intake produces a marked withdrawal syndrome (Kenny &
Markou, 2001) whose characteristics often include changes in autonomic and cortical
arousal as well as cognitive and physiological deficits evidenced by impaired

29
performance on a variety of tasks. However, nicotine administration by smoking or
other forms of nicotine delivery in nicotine-dependent individuals desensitizes the excess
number of nAChRs back to a normal level of overall activity, reducing the symptoms of
withdrawal.
Nicotine effects on behavior and brain electrophysiology are quite complex
pharmacologically because nicotine causes increased activity in acetylcholine,
norepinephrine, dopamine, serotonin, GABA, glutamate, opioid and histominergic
systems (Henningfeld & Keenan, 1993; Levin & Simon, 1998; Ochoa, 1994). Therefore,
by stimulating the release of various neurotransmitters and by modulating the effects of a
wide diversity of transmitter pathways, nicotine may provide a multi-mechanistic action
for the improvement of cognitive mechanisms.
Brain imaging studies suggest that nicotine selectively increases brain activation
in areas that include the three attentional subsystems described by the Posner and
associates neural network model as well as areas traditionally associated with arousal and
motor activation. Specifically, nicotine affects regional cerebral blood flow (rCBF) in
parieto-occipital regions in smokers and nonsmokers (Ghatan et al., 1998), and activation
in portions of the frontal, parietal, occipital, insula, and temporal cortex and subcortical
limbic regions (nucleus acumbens, amygdala and thalamus), measured as blood oxygen
level dependent (BOLD) response in nonabstinent smokers (Stein et al., 1998). In mildly
abstinent smokers nicotine replacement increases brain activation in the parietal cortex,
thalamus and caudate (Lawrence et al., 2002).

30
Summary
When habitual cigarette smokers abstain from smoking, they experience a
nicotine withdrawal syndrome which includes a myriad of negative affective and
cognitive symptoms due to the effect of nicotine on the central nervous system.
According to the brain imaging studies nicotine increases brain activation in areas
that include the three attentional subsystems described by the Posner and associates
neural network model as well as areas traditionally associated with motor activation.

31
Chapter 7
Summary and Purpose of Experiments
To summarize the previous chapters, the purpose of the two experiments
described here was to investigate the specific attentional processes that are affected by
nicotine intake and nicotine abstinence in smokers compared to nonsmokers following
continued abstinence.
The secondary goals of these studies were first, to determine whether the effects
of nicotine systematically vary between male and female smokers; and second, to
determine whether nicotine intake facilitates attentional processes in smokers to a level
beyond that of nonsmokers. A final goal was to determine whether the physiological
indices of attention measured in Experiment 1 are predictive of behavioral performance
measured in Experiment 2.
The two experiments were designed to investigate the specific attention processes
that are affected by nicotine intake and nicotine abstinence in smokers compared to
nonsmokers based on the neural network model proposed by Posner and associates (Fan
& Posner, 2004; Posner et al., 2007; Posner & Peterson, 1990), one that divides the
attention system into three distinct networks mediated by three anatomical areas of the
brain that are independently responsible for the three main attentional functions, alerting,
orienting and executive function.

32
To achieve the secondary goal of determining whether the physiological indices
of attention are predictive of behavioral performance as well as to test the effects of
autonomic arousal on the stages of attention, skin conductance was measured during both
experiments 1 and 2.

33
Chapter 8 Experiment 1
Effects of nicotine abstinence on skin conductance and prepulse inhibition
Converging evidence reported on the effects of nicotine intake and its abstinence
has suggested that nicotine intake enhances and its abstinence disrupts the early processes
of attention that involve the intake and processing of incoming stimuli as well as the
screening out of irrelevant extraneous stimuli. The process of screening out stimuli has
been referred to as a stimulus barrier (Friedman, Horvath, & Meares, 1974), stimulus
filter (Knott, 1978) and sensorimotor gating (Braff & Geyer, 1990). Following the neural
network model of attention proposed by Posner and associates (Fan & Posner, 2004;
Posner et al., 2007; Posner & Peterson, 1990) the intake and processing of incoming
stimuli involves the attentional processes of orienting, executive function and alerting
when perceptual processing of the stimulus occurs.
SC Responses
When early attentional processes are measured using SCORs the evidence
indicates that following smoking the mean number of trials to habituation and/or number
of responses to tone stimuli are reduced during passive tasks (Golding & Mangan, 1982a;
Lyvers, Boyd, & Maltzman, 1988). During an active attention task smoking has also been
shown to reduce SCOR magnitude compared to abstinence (Boyd & Maltzman, 1984).
However, sham smoking has also been reported to reduce SCOR magnitude compared to
a no smoking group (Golding & Mangan, 1982b). Boyd & Maltzman (1984) suggest that
the reduction in SCOR magnitude may be due to the biphasic response of nicotine, where
in the absence of task demands nicotine has an arousing effect while in the presence of

34
task demands nicotine has a sedating or calming effect. However, this proposal is
contrary to the reports of a reduction in the number of responses during passive tasks. An
alternative proposition is that following smoking early attentional processes are enhanced
and therefore more efficient, resulting in reduced number of responses and quicker
habituation.
Defensive SCRs reportedly show mixed results. Golding and Mangan (1982b)
reported that smoking a medium nicotine cigarette decreased defensive SCR amplitude
and increased the habituation rate to aversive white noise stimuli compared to a no
smoking control condition. However, Knott (1984) reported that following normal
smoking, smokers had greater defensive SCR response amplitudes to aversive white
noise stimuli than nonsmokers, and that female smokers had higher amplitude than all
other groups.
The evidence cited suggests that nicotine intake affects the attentional process of
orienting measured by the SCOR and that orienting is disrupted during abstinence
compared to smoking. However, the attentional modulation of the SCOR has yet to be
tested; therefore whether abstinence from nicotine disrupts the attentional process of
executive function is uncertain. The reported decreased amplitude and faster habituation
of the defensive SCR by Golding and Mangan (1982b) concurs with earlier theories that
suggest that nicotine enhances the blocking out or filtering of aversive stimuli (Friedman
et al., 1974; Knott, 1978).

35
PPI
More recent information processing models refer to the stimulus barrier or filter
as sensorimotor gating (Braff & Geyer, 1990), where inhibition of the startle response to
aversive stimuli has been argued to ‘‘protect preattentive stimulus processing allowing
for finer stimulus analysis to proceed with minimal interruption during the critical period
needed for stimulus recognition’’ (Graham, 1980, p. 512).
The literature on the enhancing (intake) and disruptive (abstinence) effects of
nicotine on PPI is more extensive than the literature on skin conductance orienting.
Several studies employing a passive PPI paradigm have reported that nicotine improves
the protection of early stimulus processing in smokers when measured by startle blink
(Della Casa, Höfer, Weiner, & Feldon, 1998; Duncan et al., 2001; Kumari, Checkley, &
Gray, 1996; Postma et al., 2006).
Della Casa et al. (1998) investigated whether nicotine enhances PPI in male and
female smokers by comparing smokers (who smoked their preferred brand of cigarette ad
libitum), deprived smokers (who abstained overnight 8 h) and smokers who abstained
overnight (8 h) then smoked their preferred brand of cigarette during the session at timed
intervals. Nonsmokers were nicotine abstinent. Smoking during the session enhanced
PPI. Specifically, in men, ad lib smoking enhanced PPI compared with nonsmokers. In
women, deprivation reduced PPI and smoking restored PPI to the level of nonsmokers.
The results suggest that nicotine may have a differential effect on men and women
smokers.

36
Kumari, Checkley, and Gray (1996) investigated whether nicotine enhances PPI
in male smokers. PPI was measured in smokers following an overnight abstinence (8 h)
and again after smoking their preferred brand of cigarette. Smoking after overnight
deprivation increased PPI compared to the smoking deprived condition.
Duncan et al. (2001) also investigated whether nicotine enhances PPI in male
smokers. Following an overnight abstinence and again after smoking their preferred
brand of cigarette. Nonsmokers were tested once following continued abstinence. During
abstinence smokers had comparable PPI to nonsmokers. However, smoking following the
abstinence test produced an improvement in PPI that exceeded that of the nonsmokers.
An improvement in itself above that following abstinence is not an indication of
facilitation. However, the reported improvement above that of nonsmokers does suggest
possible facilitation.
Two studies have measured the effects of nicotine on PPI in nonsmoker subjects.
Kumari, Cotter, Checkley, and Gray (1997), in a double-blind placebo-controlled trial,
investigated the effects of two doses (6 mg/kg, 12 mg/kg) of acute subcutaneous nicotine
on PPI in male nonsmokers. Each subject received three injections (placebo [saline], 6
mg/kg nicotine, 12 mg/kg nicotine) on separate occasions, two weeks apart. PPI was
significantly greater when subjects were given the 12 mg/kg dose of nicotine than saline.
There was an increase in PPI from saline through low to high doses of nicotine, but PPI
observed under the low dose did not differ significantly from either the high dose or
placebo.

37
Postma et al. (2006) investigated whether nicotine enhances tactile PPI in
healthy subjects and patients with schizophrenia by employing a double-blind, placebo-
controlled cross-over design. Healthy nonsmokers and smoking schizophrenia patients
underwent testing for tactile PPI on two occasions, two weeks apart, once after receiving
12 mg/kg body weight of nicotine (subcutaneously) and once after receiving saline
(placebo). Nicotine reportedly enhanced tactile PPI in both groups.
The studies cited offer evidence that nicotine intake and abstinence affect early
stimulus processing as measured by PPI. However during each study a passive attention
paradigm was employed exclusively, which therefore did not allow for the measurement
of attentional modulation of the startle eyeblink response.
One paradigm that tested the effects of smoking and abstinence on selective
attention is the CPT/PPI paradigm. Rissling, Dawson, Schell and Nuechterlein (2007)
measured startle eyeblink modification during a degraded stimulus continuous
performance test following both smoking and overnight abstinence (8 h) to measure the
effects of smoking on selective attention. A group of nonsmokers was tested twice
without nicotine manipulation. Startle inhibition was greater following targets than
nontargets following smoking and during both nonsmoker tests, but this attentional
modulation was absent following abstinence. The results are consistent with the
conclusion that smoking abstinence disrupts the early processing of attended stimuli.
All the previous studies indicated decreased PPI during short lead intervals (i.e.
30, 60, 120, 240 ms) following abstinence when compared to nicotine intake. The results
suggest nicotine affects the early stages of attention during stimulus detection and

38
discrimination which coincide with the processes of orienting and executive function in
the Posner et al. neural network model (Figure 2).
Purpose
The main goal of Experiment 1 was to test whether nicotine intake and abstinence
affect the early processes of attention measured as physiological indices of orienting and
executive function (Figure 1). The secondary goals of Experiment 1 were first, to
determine whether the effects of nicotine systematically vary between male and female
smokers and second, to determine whether nicotine intake facilitates physiological
indices of attention in smokers to a level beyond that of nonsmokers. These specific aims
were achieved by employing a standard skin conductance orienting paradigm (Passive
Attention phase) as well as a standard auditory startle eyeblink modification paradigm
(Active Attention phase).
Predicted Results
It was hypothesized that nicotine intake would enhance the early processes of
attention (orienting, executive function) resulting in greater efficiency. Therefore, during
smoking compared to abstinence it was hypothesized that: (1) overall passive SCOR
magnitude and number of responses will be lower; (2) overall passive SCDR magnitude
and number of responses will be lower; (2) greater differential SCOR magnitude will be
seen between the to-be-attended and to-be-ignored stimuli; (3) greater overall PPI will be
seen and (4) greater attentional modulation of PPI will be seen. Analyses regarding
gender or a potential facilitating effect of nicotine on SCORs or PPI during smoking
compared to nonsmokers are exploratory.

39
Methods
Subjects
Participants were 79 volunteers (34 smokers, 45 nonsmokers) from the
undergraduate student population at the University of Southern California, who signed
the University Park Institutional Review Board, approved consent form and participated
in experiments 1 and 2.
Smokers were defined as smoking at least an average of 10 cigarettes a day. Non-
smokers were defined as someone who had not ever been a regular smoker or other form
of tobacco user and who was currently abstinent from cigarette or other forms of tobacco
use.
The data for 8 participants (4 smokers, 4 nonsmokers) were excluded because of
substance use, alcohol consumption or incomplete testing (only one test completed). The
data for 2 participants (1 smoker, 1 nonsmoker) were excluded because of equipment
malfunction. A final sample of 69 participants, 29 smokers (14 male, 15 female) and 40
nonsmokers (19 male, 21 female) remained (Table 1).

40
Table 1.
Participant Characteristics Experiment 1
Note. S(smoker) NS (nonsmoker) NA (not applicable) FTQ-Fagerstrom Tolerance Questionnaire. Co PPM- carbon monoxide parts
per million.
Total Age Cigarettes Smoked Daily Years Smoking FTQ
Co PPM
Smoking
Co PPM
Abstinent
Group Male Female Mean Range Mean Range Mean Range Mean Range Mean Range Mean Range
Smokers 14 15 21 18-26 15.73 10-30 4.11 1-11 6 3-8 17.55 4-60 6 1-12
Nonsmokers 19 21 21.03 18-26 NA NA NA NA NA NA NA NA NA NA

41
Exclusions and Outlier Analysis
Subjects scoring less than an average of 1.0 µV to startle-alone trials (based on
the average of all 10 ITI startle-alone trials) were considered non-responders and were
excluded from analysis involving PPI. A total of 9 subjects (7 smokers, 4 nonsmokers)
met this criterion. Furthermore, subjects whose count of the target tones was 4 or more
off the correct count were excluded due to an inability to perform the task adequately. A
total of 13 subjects (4 smokers, 9 nonsmokers) met this criterion. This left a total of 47
subjects (20 smokers, 27 nonsmokers) for the PPI analyses and a total of 59 subjects (27
smokers and 32 nonsmokers) for the skin conductance measures during the active
attention task.
Design
This experiment employed a basic 2 Condition (smoking, abstinence) x 2 Gender
(male, female) x 2 Stimuli Type (target, nontarget) mixed design for the smoker group
and a 2 Condition (pseudo-smoking, pseudo-abstinence) x 2 Gender (male, female) x 2
Stimuli Type (target, nontarget) mixed design for the nonsmoker group.
To allow for comparisons between the smokers and nonsmokers the order of the
nonsmoker tests were counterbalanced by matching the pseudo smoking and pseudo
abstinence tests with the order of the smoking groups’ smoking and abstinence tests.
Procedures
All participants filled out a health questionnaire in order to screen for possible
confounds due to medication use, mental illness, alcohol consumption or drug use.
Further, vision and hearing levels were measured to insure that no uncorrected

42
impairments were present. Smoker participants filled out the Fagerstrom Tolerance
Questionnaire (FTQ, 1978) to rate their level of nicotine dependence and had expired
carbon monoxide (CO) levels measured to verify abstinence.
The two conditions for the smoker sample consisted of overnight nicotine
abstinence and a smoking session approximately one week apart. The order of the
conditions was randomly counterbalanced across subjects. During the abstinence session
abstinence began at 9:00 PM the night before testing and continued until the conclusion
of the session beginning either at 9:30 or 10:30 AM, resulting in at least 12 hours of
abstinence. Abstinence was confirmed with the use of an expired carbon monoxide breath
analyzer (see Table 1). Following the procedures of Kumari and Gray (1999) all smoker
participants’ expired carbon monoxide level was required to be 12 parts per million
(PPM) or below for them to be considered abstinent. No smoker participants were
dropped due to a CO level above 12 PPM. During the smoking condition participants
smoked ad lib prior to arrival at the laboratory and again ten minutes prior to the testing
session to control time since last cigarette. The nonsmoker group completed two identical
test sessions approximately one week apart with continued abstinence from nicotine. The
order of the test sessions for the nonsmokers was counterbalanced as either pseudo
smoking or pseudo abstinence.
Upon arrival to the laboratory, subjects were asked to read and sign a consent
form and were given some brief instructions. After reading these items, subjects were
instructed to wash their hands with soap and water. Next, electrodes were attached for
recording of skin conductance and EMG responses.

43
Passive Orienting. The Passive Orienting phase of the experiment began with
the subjects instructed to sit quietly in the subject chair with the headphones on and to do
their best not to move. Subjects were instructed that they would first hear some tones,
then some loud static bursts in the headphones and that they should just sit and listen. The
subjects were then presented ten tones each 1 s in duration through the headphones while
skin conductance responses were recorded. The inter-trial intervals between tones were
random and consisted of either 10, 15 or 20 seconds. The tones were1000 Hz in
frequency, 1 s in duration, 70 dB (A weighting) in intensity, with controlled rise and fall
times of 25 ms.
During the Active Attention phase the startle eliciting stimuli consisted of a 105
dB(A) white noise burst 50 ms in duration with a near instantaneous rise/fall time. The
low and high pitch tones were 800 Hz and 1200 Hz respectively, 70 dB (A) in intensity,
with controlled rise and fall times of 25 ms.
Passive Defensive Responses. Prior to the presentation of the white noise bursts
the subjects were instructed that they would now hear some static bursts and were
reminded just to sit still and do their best not to move. The subjects were then presented
with five white noise bursts 105 dB(A), 1 s in duration with a near instantaneous rise/fall
time, while skin conductance responses were recorded. The inter-trial intervals between
noise bursts were random and consisted of either 10, 15 or 20 seconds. The Passive
Orienting phase of the experiment lasted approximately 5 minutes.
Active Attention Phase. The Active Attention phase of the experiment began with
subjects instructed that they would now hear a series of tones that would include high and

44
low as well as short and long tones. Next the subjects were given an example of each
type of tone to acquaint them with the stimuli. The subjects were then reminded that the
stimuli would include short and long, high and low tones. The subjects were instructed
that during the task they were to count and keep track of the long (high or low) tones and
to ignore the rest. The target indication of high or low tones was randomized per subject
and counterbalanced by session, so that each subject had as his/her target tone the high
tone on one session and the low tone on another. Next the subject was given an example
of the target tone to verify that it could be distinguished. The subjects were asked whether
the tone was high or low and whether it was long or short. After it was presented the
subjects were reminded that the tone presented was their target tone and that it was their
job to count and keep track of it each time it was presented. Next the subjects were given
two examples of the startle stimuli and were instructed that they would be presented at
times during the tones and also at times when no tones were presented. Before beginning
the task the subjects were instructed that when they counted the long (high or low) tones
they should do it silently, not aloud, and that they should sit as still as possible during the
task.
During the active attention phase, the tones served as prepulses in a prepulse
inhibition paradigm in which 36 trials were presented. The trials were presented in a
mixed pseudo-random order. Each type of tone (high short, high long, low short, low
long) was presented 9 times. Six out of the nine prepulses of each type were probed with
three startle probes each at 60 ms and 120 ms lead intervals. The other three trials were
not probed and were “clear” trials in order to record skin conductance responses (SCRs)

45
to uncontaminated prepulses. Therefore, a total of 24 probed prepulse trials resulted.
The inter-trial intervals consisted of either 10, 15 or 20 seconds and were block
randomized. For each prepulse type at each lead interval for both the attended and
ignored stimuli, an average of the responses to the three prepulses was calculated. A total
of ten inter-trial-intervals (ITI) startle-alone white noise probes were also presented that
served to measure the subjects’ baseline startle responding. Responses to these ten ITI
probes were averaged to create a startle-alone baseline for each subject. The
randomization of the six possible types of trials (clear attend, clear ignore, probed 60 ms
attend, probed 60 ms ignore, 120 ms attend, 120 ms ignore) were accomplished using a 6
x 6 Latin square.
The active attention task lasted approximately 12 minutes. At the end of the task
subjects were asked how many of the target tones they counted. Out of the 36 trials nine
were target tones (six probed and three clear).
Experimental Stimuli. The durations of the tones were 3 s and 4 s for the short and long
tones respectively. All auditory stimuli were presented binaurally through Telephonics
TDH-50P headphones. Decibel levels were calibrated with a Realistic sound level meter
using a Quest Electronics Earphone Coupler.
Recording and Scoring of Dependent Variables
Stimulus presentation and data acquisition were controlled through Contact
Precision Instruments by a computer running SAM software. Both the raw EMG (filtered
at 10 Hz high pass and 500 Hz low pass) and skin conductance signals were collected at a

46
rate of 1000 Hz. The data were stored and exported for analysis in microvolt values for
EMG and microSiemens (µS) for skin conductance.
Eye blinks were collected and scored as EMG activity of the orbicularis oculi
muscle of the left eye according to standard procedures (see Blumenthal et al., 2005).
One small (4mm) silver-silver chloride (Ag-AgCl) electrode was placed on the left eyelid
directly below the pupil while a second 4 mm electrode was placed approximately 1 cm
lateral to the first. The impedance between the two electrodes was measured and deemed
acceptable if below 10 K Ω. A large (8mm) Ag-AgCl electrode was placed behind the left
ear to serve as a common ground. Skin conductance data were collected using standard
procedures (Dawson, Schell, & Filion, 2007) using two 8 mm Ag-AgCl electrodes, filled
with isotonic conductive paste, placed on the volar surface of the distal phalanges of the
index and middle finger of the subject’s non-dominant hand. A constant 0.5 V DC was
applied across the electrodes.
For analysis, the EMG signal was software integrated using a 10 ms time
constant. Startle response onset was set to be detected within a window of 20-120 ms
while peak activity was set within a window of 20-200 ms. SCORs were scored as a
response beginning between 1-4 seconds after stimulus onset, having an amplitude of at
least .05 µS. The mean magnitude and number of orienting responses were scored and
recorded. NS-SCRs were defined as responses of at least 0.05 µS recorded 5 s prior to
each tone and were expressed as the total number over the ten passive orienting trials. All
skin conductance response magnitudes were square root transformed for data analysis.

47
Prepulse inhibition was calculated as percent change score defined as:
% 100
magnitude startle baseline Average
magnitude startle baseline Average - prepulse during magnitude Startle
×
to determine the amount of inhibition or facilitation at each lead interval (60 ms, 120 ms)
during to-be-attended and to-be-ignored trials. Therefore, a negative percent change
indicates inhibition of the startle eyeblink by the prepulse while a positive percent change
indicates facilitation of the startle eyeblink. Percent change units are preferred over
difference scores (Startle magnitude during prepulse – average baseline startle
magnitude) because difference scores in absolute µV units are correlated with baseline
startle blink amplitude whereas percent change scores are not, removing any dependence
on baseline startle amplitude (Jennings et al., 1996). Individual percentage change scores
were collapsed into mean target, nontarget and inter-trial interval scores by lead interval
(60 ms, 120 ms) by subject.
Skin conductance responses were first compressed into a sampling rate of 20 Hz.
Specific comparisons for all dependent variables were performed using repeated
measures and independent sample t-tests with an α level of 0.05. All t-tests were 2-tailed
unless otherwise specified. Rom’s sequentially rejective method was utilized for the
control of family wise type I error (Rom, 1990) for all multiple t-tests. An estimate of
effect size (d, Cohen, 1988) was also calculated for all specific comparisons.
Results
Passive SCOR, Smoker Group
Mean passive SCOR magnitude scores to the tone stimuli for smokers and
nonsmokers are shown in Figure 5. A series of t-tests was conducted to verify that

48
significant orienting had occurred (means significantly greater than 0). During each
condition all t-values were significant, p < .001.
To test the effects of smoking and abstinence on passive SCOR magnitude across
gender, a condition x gender ANOVA for the smoker group was conducted and resulted
in no main effects or interactions.

49
Figure 5: SCOR and SCDR Magnitude during the passive attention phase across
conditions

50
Proportion of SCORs, Smoker Group
The proportion of orienting and defensive skin conductance responses for the
smoker and nonsmoker groups during the two conditions are shown in Figure 6. To test
the effects of smoking and abstinence on the passive SCOR the proportion of responses
(number of SCORs divided by total presentations) across gender, a condition x gender
ANOVA for the smoker group was conducted and resulted in no main effects or
interactions.
Passive SCOR, Nonsmoker Group
A series of t-tests was conducted to verify that significant orienting had occurred
(means significantly greater than 0). During each condition all t-values were significant, p
< .001.
To test whether there was a change over the two comparable tests for the
nonsmoker group or across gender a condition (pseudo-smoking, pseudo-abstinence) x
gender (male, female) ANOVA for the nonsmoker group was conducted and resulted in
no main effects or interactions.
Proportion of SCORs, Nonsmoker Group
To test whether there was a change over the two comparable tests for the
nonsmoker group on passive SCOR, the proportion of responses (number of SCORs
divided by total presentations) across gender, a condition x gender ANOVA for the
nonsmoker group was conducted and resulted in no main effects or interactions.

51
SCDR, Smoker Group
To test the effects of smoking and abstinence on SCDR magnitude an overall 2
condition (smoking, abstinence) x 2 gender (male, female) ANOVA for the smoker group
resulted in no statistically reliable main effects or interactions.

52
Figure 6: Proportion of SCOR and SCDR responses during the passive attention phase.

53
Proportion of SC DRs, Smoker Group
To test the effects of smoking and abstinence on passive SCDR response rate
(number of SCDRs) across gender, a condition x gender ANOVA for the smoker group
was conducted and resulted in no main effects or interactions.
SCDR, Nonsmoker Group
To test whether there was a change over the two comparable tests for the
nonsmoker group on SCDR magnitude an overall 2 conditions (smoking, abstinence) x 2
gender (male, female) ANOVA for the nonsmoker group resulted in no statistically
reliable main effects or interactions.
Number of DRs, Nonsmoker Group
To test whether there was a change over the two comparable tests for the
nonsmoker group on SCDR response rate (number of SCDRs) across gender, a condition
x gender ANOVA for the nonsmoker group was conducted and resulted in no main
effects or interactions.
Active Attention SCOR, Smoker Group
Mean active SCOR scores to the target and nontarget stimuli for the smoker and
nonsmoker groups are shown in Figure 7. A series of t-tests was conducted to verify that
significant orienting had occurred (means significantly greater than 0). During each
condition all t-values were significant, p < .05.
The overall 2 stimulus (target, non-target) x 2 condition (smoking, abstinence) x 2
gender (male, female) ANOVA for smokers revealed a significant main effect of stimulus

54
type (F [1, 25] = 6.36; p < .05, d = .93) indicating overall increased magnitude to targets
compared to nontarget stimuli.

55
Figure 7: Mean target and nontarget SCOR magnitude during the active attention phase.

56
Active Attention SCOR, Nonsmoker Group
A series of t-tests was conducted to verify that significant orienting had occurred
(means significantly greater than 0). During each condition all t-values were significant, p
< .05.
The overall 2 stimulus (target, non-target) x 2 condition (pseudo-smoking,
pseudo-abstinence) x 2 gender (male, female) ANOVA for nonsmokers revealed only a
significant main effect of stimulus type (F [1, 30] = 4.55; p < .05, d = .77).
Baseline (ITI) EMG, Smoker Group
The mean startle eyeblink magnitude to the startle alone stimulus presented
during the baseline periods was 8.35 µV (SD =7.39 µV) during smoking and 3.36 µV
(SD = 11.90 µV) during abstinence (Figure 8).
The 2 gender (male, female) x 2 condition (smoking, abstinence) ANOVA for the
smoker group for the baseline blink magnitude resulted in no statistically reliable main
effects or interactions, indicating the mean baseline startle eyeblink amplitude between
the two tests and the genders did not significantly differ.
Baseline (ITI) EMG, Nonsmoker Group
The mean startle eyeblink magnitude to the startle alone stimulus presented
during the baseline periods was 15.26 µV (SD =20.76 µV) during pseudo-smoking and
10.75 µV (SD = 12.86 µV) during pseudo-abstinence.
The 2 gender (male, female) x 2 condition (pseudo-smoking, pseudo-abstinence)
ANOVA for the nonsmoker group for the baseline blink magnitude resulted in no

57
statistically reliable main effects or interactions indicating the mean baseline startle
eyeblink magnitude between the two conditions did not significantly differ.

58
Figure 8: Mean baseline startle eyeblink magnitude during the active attention phase.

59
Overall PPI
Mean startle eyeblink modification scores for the 60 ms lead intervals are shown
in Figure 9, while the 120 ms lead intervals are shown in Figure 10. A series of t-tests
was conducted to verify that significant startle eyeblink modification had occurred
(means significantly less than 0) for each prepulse at each lead interval. During each
condition for both smoker and nonsmoker groups all t-values were significant, p < .001.

60
Figure 9: Mean startle eyeblink magnitude at the 60 ms lead interval during the active
attention phase.

61
Figure 10: Mean startle eyeblink magnitude at the 120 ms lead interval during the active
attention phase.

62
60 ms Lead Interval PPI, Smoker Group
The overall 2 stimulus (target, non-target) x 2 condition (smoking, abstinence) x 2
gender (male, female) ANOVA for the 60 ms lead interval for smokers revealed a
significant main effect for condition (F [1, 19] = 5.14; p < .05) d = 1.03.
An analysis of the main effect of condition using a simple main effect contrast
revealed greater inhibition during the smoking condition (M = -64.04 µV) compared to
the abstinence condition (M = -52.65 µV) when averaged across target and nontarget
stimuli.
60 ms Lead Interval PPI, Nonsmoker Group
The overall 2 stimulus (target, non-target) x 2 condition (smoking, abstinence) x 2
gender (male, female) ANOVA for the 60 ms lead interval for nonsmokers resulted in no
statistically reliable main effects or interactions indicating the mean amplitude to target
and nontarget stimuli did not differ at either condition or between males and females.
120 ms Lead Interval PPI, Smoker Group
The overall 2 stimulus (target, non-target) x 2 condition (smoking, abstinence) x 2
gender (male, female) ANOVA for the 120 ms lead interval for smokers resulted in no
statistically reliable main effects or interactions indicating the mean amplitude to target
and nontarget stimuli did not differ between smoking or abstinence or between males and
females.
120 ms Lead Interval PPI, Nonsmoker Group
The overall 2 stimulus (target, non-target) x 2 condition (smoking, abstinence) x 2
gender (male, female) ANOVA for the 120 ms lead interval for nonsmokers resulted in

63
no statistically reliable main effects or interactions indicating the mean magnitude to
target and nontarget stimuli did not differ at either condition or between males and
females.
Facilitation or Withdrawal Relief
To test whether nicotine intake enhanced attentional processes beyond that of
nonsmokers a series of t-tests were conducted between the smokers during the smoking
condition and the nonsmokers during the comparable (pseudo-smoking) test for each
dependent variable.
During the Passive Attention phase no differences were found between the
smoker and nonsmoker groups for the skin conductance dependent variables: SCOR
magnitude, proportion of SCORs, SCDR magnitude, and proportion of SCDRs,
indicating no enhancement following smoking for the smoker group compared to the
pseudo smoking condition of the nonsmokers.
During the Active Attention phase no differences were found between the smoker
and nonsmoker groups for either the skin conductance or startle eyeblink dependent
variables: target magnitude, nontarget magnitude, attentional modulation scores (target –
nontarget magnitude, indicating no enhancement following smoking for the smoker
group compared to the pseudo smoking condition of the nonsmokers.
Discussion
The results of the smoking versus abstinence test sessions in the smoker group did
not indicate an enhancement of autonomic orienting as was hypothesized. The results are
inconsistent with previous passive SCOR studies that reported decreased SCOR

64
magnitude and number of SCORs following smoking (Golding & Mangan, 1982a,
1982b; Lyvers et al., 1988). It is unclear why in the current experiment the group of
smokers did not show an effect of smoking.
The passive SCOR results for the nonsmoker group indicated no differences
following pseudo-smoking and pseudo-abstinence, as was hypothesized. The lack of
differences between SCOR responding in smokers following smoking and nonsmokers
suggests there was no enhancement following smoking in smokers beyond that of
nonsmokers during a comparable test session. The lack of enhancement is not surprising
as the issue of enhancement is still controversial.
The SCDR results during the passive attention phase for the smoker group were
not significantly different during the smoking and the abstinence conditions. Therefore no
effect of smoking was observed for overnight abstinence. The results are inconsistent
with Golding and Mangan, (1982b) who reported that smoking decreased defensive SCR
magnitude. The lack of differences between male and female smokers is inconsistent with
Knott (1984) who reported that following smoking female smokers had higher SCDR
magnitude than male smokers. Although it is unclear why a lack of an effects existed, the
literature is very small regarding these effects, with only Golding and Mangan (1982b)
reporting that smoking decreased defensive SCR magnitude and Knott (1984) reporting
differential responding in males and females.
The skin conductance defensive response results for the nonsmoker group
indicated no differences following pseudo-smoking and pseudo-abstinence, as was
hypothesized. The lack of differences between skin conductance defensive responding

65
between smokers and nonsmokers suggests there was no enhancement following
smoking in smokers beyond that of nonsmokers during a comparable test session. The
lack of reports indicating an enhancing effect of smoking in smokers beyond that of
nonsmokers suggests no such enhancement exists when measured by autonomic
variables.
During the active attention phase the skin conductance orienting results for the
smoker group revealed a significant main effect of stimulus indicating increased
magnitude to target compared to nontarget stimuli. The results suggest that although
significant orienting to target stimuli compared to nontarget stimuli occurred during both
conditions, smoking had no effect compared to overnight abstinence. These results are
inconsistent with our hypotheses regarding increased target-nontarget differences
following smoking compared to overnight abstinence. To our knowledge this is the first
study to test the effects of nicotine intake and abstinence on the attentional modulation of
SCORs
During the active attention phase the skin conductance orienting results for the
nonsmoker group revealed a significant main effect of stimuli indicating increased
magnitude to target compared to nontarget stimuli.
The lack of differences of SCOR modulation scores (target – nontarget) between
the smoker group during the smoking condition and the nonsmokers during the pseudo-
smoking condition suggests there was no enhancement following smoking in smokers
beyond that of nonsmokers during a comparable test session. The results do not concur or
disagree with the hypothesized results as they were exploratory.

66
During the active attention phase the startle eyeblink results for the smoker
group revealed a significant main effect of condition on blink inhibition (PPI) at the 60
ms lead interval indicating decreased magnitude (i.e. greater PPI) during the smoking
condition compared to the abstinence condition when averaged across stimulus type.
However, as can be seen in Figure 9 the target nontarget differences were not significant
during either the smoking or the abstinence conditions and did not differ between the two
conditions. Therefore no effect of stimulus type was observed. The results suggest that
although significantly greater PPI during the smoking condition compared to the
abstinence condition occurred when averaged across target and nontarget stimuli,
smoking had no differential effect on target compared to nontarget stimuli. The results
are consistent with previous active attention PPI studies which reported no differences in
amplitude to target compared to nontarget stimuli at the 60 ms lead interval (Dawson et
al., 1993; Filion et al., 1993; Hawk et al., 2002; Jennings et al., 1996; Schell et al., 1995)
as well as with our hypotheses.
During the active attention phase the startle eyeblink results for the nonsmoker
group did not reveal any significant main effects or interactions on blink inhibition (PPI)
at the 60 ms lead interval. The results are consistent with previous active attention PPI
studies which reported no differences in amplitude to target compared to nontarget
stimuli at the 60 ms lead interval (Dawson et al., 1993; Filion et al., 1993; Hawk et al.,
2002; Jennings et al., 1996; Schell et al., 1995) as well as with our hypotheses regarding
no differences between target and nontarget stimuli at the 60 ms lead interval and no
differences between test sessions for the nonsmoker group. No enhancement of PPI was

67
observed during smoking compared to pseudo smoking at the 60 ms lead interval. The
lack of enhancement in smokers compared to nonsmokers for the 60 ms lead interval, are
consistent with the SCOR and SCDR results.
During the active attention phase the startle eyeblink results for the smoker and
nonsmoker groups did not reveal any significant main effects or interactions on blink
inhibition (PPI) at the 120 ms lead interval. The results are inconsistent with previous
active attention PPI studies which report decreased amplitude to target compared to
nontarget stimuli at a 120 ms lead interval (Dawson et al., 1993; Filion et al., 1993; Hawk
et al., 2002; Jennings et al., 1996; Schell et al., 1995) as well as with Rissling et al.
(2007) which reported smoking increased the attentional effect of PPI during a
continuous performance test. Moreover, the results indicating no difference between
smoking and abstinence are inconsistent with our hypotheses regarding increased target
nontarget differences following smoking compared to overnight abstinence. No
enhancement of PPI was observed during smoking compared to pseudo smoking at the
120 ms lead interval.
Overall the results for the PPI dependent variables were inconsistent with prior
research. The tone counting task when employed with nonsmokers without nicotine
manipulation did not show attentional modulation (increased inhibition) following target
stimuli compared to nontarget stimuli. This result is difficult to explain due to the number
of studies reporting the attentional modulation effect using similar paradigms (Dawson et
al., 1993; Filion et al., 1993; Hawk et al., 2002; Jennings et al., 1996; Schell et al., 1995)
across several laboratories. The results suggest the current paradigm was unable to induce

68
top down control by instructed significance placed on one tone verses the alternate tone.
Further, this lack of effect was not solely due to the type of tone (high or low) as both
tones were presented as the target tone on alternating test sessions and the order of which
tone (high or low) was counterbalanced across participants.
One possible explanation is that the participants habituated to the presentation of
tones. The participants were first presented ten innocuous tones (1000 Hz), followed by 5
aversive white noise bursts (105 dB(A) prior to the active attention phase. In the previous
studies cited in which an attentional effect of PPI was reported no passive orienting or
defensive responses were presented. One study (Schell, Wynn, Dawson, Sinaii, &
Niebala, 2000) reported that following a habituation phase in which the to-be-attended
tones were presented no attentional modulation of PPI occurred. Therefore, although in
the current study the tones presented during the passive attention phase were not the same
as the to-be-attended tones presented in the active attention phase, the presentation may
have taxed the participants resulting habituation and a lack of top down attentional
modulation.

69
Chapter 9 Experiment 2
Effects of nicotine abstinence on early visual processing and vigilance
During continuous performance tests (CPTs) reduced overall vigilance
performance as measured by the number of correct target detections and/or reaction time
of correct detections has been reported in smokers following nicotine abstinence when
compared to nicotine intake by smoking (Edwards et al., 1985; Gilbert et al., 2000;
Lawrence et al., 2002; Wesnes & Warburton, 1978), nicotine patch, nicotine tablets, or
nicotine gum (Mancuso et al., 1999; Parrott & Craig, 1992; Parrott & Winder, 1989;
Wesnes & Revell, 1984; Wesnes & Warburton, 1978).
In self-paced CPTs, nicotine deprivation has also been found to decrease the
processing rate, defined as the number of stimuli presented per minute (Baldinger,
Hasenfratz, & Battig, 1995; Hasenfratz, Michel, Nil, & Bättig, 1989; Michel & Bättig,
1989). However, failure to find effects for nicotine administration compared to
abstinence have also been reported (Jacobsen et al., 2005; Michel, Hasenfratz, Nil, &
Bättig, 1988; Morris & Gale, 1993; Poltavski & Petros, 2005).
Nicotine administered to nonsmokers (usually in a double blind fashion) by
various means (e.g., nicotine gum) has also been shown to facilitate performance on
various visually presented continuous performance tasks (Foulds et al., 1996; Kumari et
al., 2003; Le Houezec, Jacob, & Benowitz, 1993; Lyvers et al., 1988; Wesnes & Revell,
1984; Wesnes & Warburton, 1978).
The inconsistencies in results reported in previous studies with smokers may be
due to the use of CPTs that present clearly focused visual stimuli that are highly

70
discriminable leading to ceiling effects on accuracy. Also successive CPTs that involve
a memory component (e.g. RVIP or N-Back task) may be taxing short term memory as
opposed to perceptual processing or vigilance. Clearly focused tasks have been shown to
be only minimally taxing of perceptual processing and therefore may not be adequately
sensitive to deficits in distinguishing target from nontarget stimuli (Nuechterlein, 1983;
Rissling et al., 2005). CPTs that employ visually degraded stimuli that have low
discriminability have been shown to be sensitive to deficits in distinguishing target from
nontarget stimuli in various subject populations including smokers following abstinence
(Nuechterlein, 1991; Rissling et al., 2007). As will be discussed in the methods section
the current experiment employs tasks that manipulate the burden on early perceptual
processing as well as the vigilance requirements without the possible confounding effects
of a memory component.
Although the majority of cited evidence suggests that nicotine affects attentional
processes during CPTs, which specific processes affected is not well understood. The
neural network model of attention proposed by Posner and associates (Fan & Posner,
2004; Posner et al., 2007; Posner & Peterson, 1990) suggests that CPT performance
involves early processes of orienting and executive function in which the subject
discriminates between target and nontarget stimuli and a process of alerting which
involves the initiation and maintenance of an alert state. Manipulation of demands on the
early perceptual processes during target detection and discrimination and on later
maintenance of attention may shed light on the specific attentional processes that are
affected by nicotine intake and abstinence.

71
Variable results have been reported regarding the effect of nicotine intake and
abstinence on RT during CPTs. Among smokers following short-term abstinence,
nicotine intake has been shown to decrease RT during the Rapid Visual Information
Processing task (RVIP) when compared to a placebo group (Parrott & Winder, 1989;
Wesnes & Warburton, 1984a), a denicotinized cigarette (Baldinger et al., 1995), or a
comparable baseline (Michel & Bättig, 1989). Alternatively, Morris and Gale (1993)
reported that smoking had no effect on reaction time following short-term abstinence.
Reduced reaction time has also been reported following smoking compared to
overnight abstinence during CPTs (Edwards et al., 1985), including after two puffs
compared to abstinence and sham smoking (Revell, 1988) and RT has been shown to
have a curvilinear dose response relationship due to faster response times after 2 and 4
mg nicotine gum, compared to placebo (Parrott & Craig, 1992). In contrast, Mancuso et
al. (1999), Gilbert, Dibb, Plath, and Hiyane, (2000), and Zack et al. (2001) reported no
difference in RT following nicotine intake compared to overnight abstinence during
CPTs.
Reaction time measures may shed light on processing speed. However RT may be
confounded by effects on motor speed. Choice reaction time measurement may separate
the components of decision time and motor movement. Simple reaction time is the time it
takes to respond to a single stimulus. Examples of choice reaction time tasks are those in
which participants respond differentially to two stimuli by pressing one key for event A
and a separate key for event B and the RT for each is recorded to differentiate the two.

72
Two studies have reported reduced decision time effects following intake
compared to sham smoking (Bates, Pellet, Stough, & Mangan, 1994). Comparing
nicotine intake to abstinence Smith, Tong, Leigh, (Smith, Tong, & Leigh, 1977) also
reported reduced decision time following intake compared to abstinence. Le Houezec et
al. (1993) reported that a subcutaneous injection of 0.8 mg nicotine compared to 0.8 ml
saline significantly increased the number of responses at the fast end of the RT
distribution without changes in accuracy on a choice RT task. Similarly, Hindmarch,
Kerr, and Sherwood (1990) in Experiment 1 reported reduced simple motor reaction time
for smokers following either 2 or 4 mg nicotine gum, but no effect on recognition
(choice) RT. In Experiment 2 no effects for either recognition (choice) RT or simple
motor RT were reported for nonsmokers following 2 mg nicotine gum.
The positive results reported further suggest that nicotine affects the attentional
process of executive function during stimulus processing. Simple motor response time
has also been shown to improve following nicotine intake. However, negative findings
have also been reported.
Enhancement or Withdrawal Relief
Measuring the performance of smokers following smoking compared to
abstinence helps to answer the question of whether nicotine abstinence affects
performance. However, does nicotine intake by smokers result in an absolute
enhancement of performance or only cause a reversal of deprivation-induced
performance decrements to levels comparable to nonsmokers?

73
One study has reported performance improvements with nicotine administration
in smokers in the absence of withdrawal effects. Warburton and Arnall (1994),
employing the RVIP in two experiments, reported no difference in overall performance
on the RVIP between smokers after ten hours of abstinence and non-smokers. Further,
when comparing smokers abstinent for one hour and twelve hours, they found no
difference in performance. However, after smoking a cigarette the number of correct
target detections did reliably increase following the third puff after one hour as well as
twelve hours of abstinence. The results indicate that although there were not effects of
abstinence on performance, smoking did reliably increase performance after only three
puffs.
Improvements in performance in nonsmokers following nicotine intake have been
reported (Foulds et al., 1996; Kumari et al., 2003; Le Houezec et al., 1993; Lyvers et al.,
1988; Wesnes & Revell, 1984; Wesnes & Warburton, 1978) and studies have reported an
improvement in the performance of smokers without the effects of abstinence (Warburton
& Arnall, 1994) indicating an overall enhancement. However, the evidence is mixed.
Thus, the question whether the enhancement in performance with smokers is comparable
to the normal level of nonsmokers or a true enhancement above the level of nonsmokers
requires further investigation.
Purpose
Experiment 2 was conducted to test whether nicotine intake and abstinence affect
the attentional processes of orienting and executive function or maintaining vigilance

74
(Figure 3). A second goal was to test whether nicotine intake facilitates attention
performance beyond that of nonsmokers.
To accomplish the first goal three CPTs were employed that manipulated the
burden on early perceptual processing and maintaining vigilance. The three tasks
employed were the degraded stimulus alerted performance test (DS-APT), the zero
continuous performance test (Z-CPT) and the degraded stimulus continuous performance
test (DS-CPT). The DS-APT uses a 40% random pixel reversal to degrade the stimuli
placing a large burden on early visual processing during the processes of orienting and
executive function. However, the pace of the digits is determined by the subject.
Therefore, no demands are placed on maintaining vigilance. The second task, the Z-CPT,
places a burden on maintaining vigilance by presenting the digit stimuli at a fast pace.
However, due to the clear stimuli presented no burden is placed on early visual
processing. The DS-CPT places a burden on both the early visual processing due to a
40% random pixel reversal to degrade the stimuli and to the fast pace of digit
presentation.
To accomplish the second goal the data from the smoker group following
smoking was compared with the data from the nonsmoker group following a comparable
nonsmoking test.
Predicted Results
It was hypothesized that nicotine would facilitate the early processes of attention
(orienting, executive function). It was hypothesized that the effects would be evidenced
among smokers during abstinence by overall lower d ′ and slower RT in the DS-CPT and

75
DS-APT. No differences were hypothesized between conditions for d ′ or RT during the
Z-CPT for smokers. No differences in nonsmokers were hypothesized between the two
conditions (pseudo-smoking, pseudo- abstinence) for any CPT or the dependent variables
d′ or RT. No differences were hypothesized between the two groups for the dependent
variables d ′ or RT. No directional differences were hypothesized between male and
female smokers or male and female nonsmokers, all gender analyses were exploratory.
Methods
Participants
Participants were 79 volunteers (34 smokers, 45 nonsmokers) from the
undergraduate student population at the University of Southern California, who signed
the University Park Institutional Review Board approved consent form and participated
in Experiments 1 and 2.
The data for 8 participants (4 smokers, 4 nonsmokers) were excluded because of
substance use, alcohol consumption or incomplete testing (only one test completed). A
final sample of 71 participants, 30 smokers (15 male, 15 female) and 41 nonsmokers (18
male, 23 female) remained (Table 2).

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Table 2.
Participant Characteristics Experiment 2
Total Age Cigarettes Smoked Daily Years Smoking FTQ
Co PPM
Smoking
Co PPM
Abstinent
Group Male Female Mean Range Mean Range Mean Range Mean Range Mean Range Mean Range
Smokers 15 15 21.33 18-26 15.88 10-30 4.1 1-11 5.9 3-8 17.63 3-60 6 1-12
Nonsmokers 18 23 21.72 18-33 NA NA NA NA NA NA NA NA NA NA
Note. S(smoker) NS (nonsmoker) NA (not applicable) FTQ-Fagerstrom Tolerance Questionnaire. Co PPM- carbon
monoxide parts per million

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Design
This experiment employed a basic 2 condition (smoking, abstinence) x 2 Gender
(male, female) mixed design for the smoker group separately for each task (DS-APT, Z-
CPT, DS-CPT) and a 2 condition (pseudo-smoking, pseudo-abstinence) x 2 Gender
(male, female) mixed design for the nonsmoker group separately for each task (DS-APT,
Z-CPT, DS-CPT). The three tasks were analyzed separately due to the nature of the
burden placed on attentional processing during each task. Although d ΄ measured the
sensitivity of the participants during each task the processes tested were different,
therefore analyzed separately.
Procedure
Following the completion of Experiment 1 the EMG sensors were removed from
below the participants’ left eyes and from behind their left ears. Experiment 2 began with
the verification of the participants’ normal or corrected to normal vision or hearing
(vision during session1, hearing during session 2). No participants were excluded for
either poor vision or hearing. Next the subjects were seated with their eyes at a distance
of one meter from the computer monitor.
Experiment 2 consisted of three continuous performance tasks in the following
order: the Degraded Stimulus Alerted Performance Test (DS-APT), the Zero Continuous
Performance Test (Z-CPT), and the Degraded Stimulus Continuous Performance Test
(DS-CPT). Each task consisted of four phases: examples, long duration practice, standard
duration practice and standard duration test trials. The variations in the three tasks
consisted of the discriminability of the digit stimuli (see Figure 4), rate of digit

78
presentation, and the number of blocks of stimuli during the standard duration test trials.
Each block of stimuli consisted of 160 single digits that were identical during each task
and across all three tasks.
Stimuli. During each task a series of single digits (0-9) were presented pseudo-
randomly one at a time on a computer monitor with an exposure time of 29 ms. The rate
of digit presentation of the Z-CPT and DS-CPT was 1 per second. The rate of digit
presentation of the DS-APT was controlled by the subject. The target was the digit 0 and
was presented at a .25 rate of probability. Each single block of 160 stimulus presentations
consisted of 40 single “0”s, and 120 nontargets (1-9). Each block of 160 stimuli during
the DS-CPT and Z-CPT consisted of a continuous observation period of approximately
2.5 minutes. During the DS-CPT and DS-APT tasks a 40% random black/white pixel
reversal visually degraded the stimuli. The computer recorded reaction time in
milliseconds to all button presses and calculated hit rate and false alarm rates for the
calculation of d ′ and β.
DS-APT. The DS-APT is a visual perception task that examines discrimination of
visually degraded single digits in an alerted condition in which the subject controls the
presentation rate of the stimulus. The same stimuli are presented by the computer
program as in the Degraded-Stimulus CPT, but the subject initiates each presentation by
saying “Go” to the tester to indicate readiness. The tester then presses the space bar on
the computer keyboard to present a stimulus. Therefore the DS-APT places a burden on
early visual processing without a burden on sustaining vigilance due to the subject
controlling the pace.

79
The participants were instructed that their task was to watch a series of single
digits that would be presented briefly (29 ms exposure time) but that the rate at which the
numbers would appear would be up to them. Specifically, every time they were ready to
see a number they should say "go" and the next number would be presented. The subjects
were instructed to go at their own pace and to take as many breaks to rest as necessary
and that it was important that they be ready to see a new number each time they said
“go”. They were further instructed that their task would be to press a response button
with the index finger of their dominant hand each time they saw a zero and to refrain
from pressing the button at any other time.
After instructions ten examples of the degraded target zeros with an extended
exposure time of 290 ms were shown to the participants (examples). Participants were
next shown a block of 80 examples of the digits with an extended exposure time (290
ms). The first ten digits were read to the subject aloud by the experimenter. The
participants were then asked to read aloud the digits they saw on the screen to verify that
they could discriminate the degraded digits. Lastly, the participants were instructed to
practice pressing every time they saw a zero (slow duration practice).
Next the participants were asked to practice pressing each time they saw a zero
while one block of 160 digits were presented at the normal exposure rate of 29 ms at the
subject’s own pace (standard duration practice). Finally, during the standard duration test
trials the participants were asked to say “go” every time they were ready to see a number
and to press each time they saw a zero while one block of 160 digits were presented at the
normal exposure rate of 29 ms.

80
Z-CPT. The zero CPT (Z-CPT) is a vigilance task that requires discriminations
between clear stimuli that are presented briefly at the same digit presentation rate as the
DS-CPT. Due to the high discriminability of the digits the burden on vigilance is solely
due to the presentation rate.
During the Z-CPT a total of 480 trials including 120 targets were used, to have
enough trials for reliable assessment of d ΄ as well as to put a burden on maintaining
vigilance. This allowed testing of the extent to which the deficit in target/nontarget
discrimination in cigarette smokers while abstaining is attributable to vigilance demand.
The participants were instructed that their task was to watch a series of single
digits that would be presented briefly (29 ms exposure time) and rapidly (1 s between
digits) on the computer monitor in front of them. They were further instructed that their
task would be to press a response button with the index finger of their dominant hand
each time they saw a zero and to refrain from pressing the button at any other time.
Following the instructions ten examples of the clearly focused zeros with an
extended exposure time of 290 ms were shown to the participants. The participants were
then asked to practice pressing each time they saw a zero while one block of 160 digits
were presented at the normal exposure rate of 29 ms.
Finally, during the standard duration test trials the participants were asked to press
each time they saw a zero while three blocks of 160 digits each (480 total) were presented
at the normal exposure rate of 29 ms.
DS-CPT. The Degraded Stimulus Continuous Performance Task (DS-CPT) is a
vigilance task that requires very subtle perceptual discriminations between blurred stimuli

81
at a rapid pace (Nuechterlein, 1983). The perceptual degradation of the stimuli in the
DS-CPT requires greater and more sustained allocation of attentional resources due to the
increased burden on perceptual analysis and the quick presentation rate. The increased
allocation of attentional resources is evidenced by decreases in overall vigilance
(Nuechterlein, 1983) and an increased reaction time (Rissling et al., 2005) when
compared to a task with clear digits.
During the DS-CPT a total of 480 trials including 120 targets were used, to have
enough trials for reliable assessment of d΄ as well as to put a burden on early visual
processing as well as to maintaining vigilance. This allowed testing of the extent to which
the deficit in target/nontarget discrimination in cigarette smokers while abstaining is
attributable to basic perceptual analysis difficulty as well as to vigilance demand.
The participants were instructed that their task was to watch a series of single
digits that would be presented briefly (29 ms exposure time) and rapidly (1 s between
digits) on the computer monitor in front of them. They were further instructed that their
task would be to press a response button with the index finger of their dominant hand
each time they saw a zero and to refrain from pressing the button at any other time.
Following instructions ten examples of the degraded target zeros with an extended
exposure time of 290 ms were shown to the participants. Participants were next shown a
block of 80 examples of the digits with an extended exposure time (290 ms). The first ten
digits were read to the subject aloud by the experimenter. The participants were then
asked to read aloud the digits they saw on the screen to verify that they could
discriminate the degraded digits. Lastly, the participants were instructed to practice

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pressing every time they saw a zero. Next the participants were asked to practice
pressing each time they saw a zero while one block of 160 digits were presented at the
normal exposure rate of 29 ms.
Finally, during the standard duration test trials the participants were asked to press
each time they saw a zero while three blocks of 160 digits each (480 total) were presented
at the normal exposure rate of 29 ms.
Recording and Scoring of Dependent Variables. The primary dependent variables
were the speed and accuracy of button press responses. The computer recorded hits
(correct target detections), false alarms and reaction times in milliseconds. To measure
behavioral performance, the correct hit rate and false alarm rate were used to calculate d ΄
values. To measure possible response bias, the natural log of beta was calculated. As a
second measure of behavioral performance, reaction time was recorded in milliseconds
on correct responses to target trials.
The secondary dependent variable was skin conductance level (SCL). Skin
conductance data were collected using standard procedures (Dawson et al., 2007) using
two 8 mm Ag-AgCl electrodes, filled with isotonic conductive paste, placed on the volar
surface of the distal phalanges of the index and middle finger of the subjects non-
dominant hand. A constant 0.5 V DC was applied across the electrodes.
Specific a priori comparisons were conducted using planned interaction contrasts
with an α level of 0.05. Post hoc comparisons were conducted using simple effects
contrasts and repeated measures and independent sample t-tests with an α level of 0.05.
All t-tests were 2-tailed unless otherwise specified. Rom’s sequentially rejective method

83
was utilized for the control of family wise type I error (Rom, 1990) for all multiple t-
tests. An estimate of effect size (d, Cohen, 1988) was also calculated for all specific
comparisons.
Results
d-Prime (DS-APT)
Figure 11 shows the mean overall vigilance level values (d ΄) for smokers and
nonsmokers during the two conditions for the DS-APT. A condition x gender ANOVA
for the smoker group during the DS-APT revealed a significant main effect for condition
(F [1, 28] = 12.34; p < .01, d = 1.32) indicating increased d ΄ following smoking (M =
3.64) compared to abstinence (M = 3.08) when averaged across gender.
A condition x gender ANOVA for the nonsmoker group during the DS-APT did
not result in any significant main effects or interactions, indicating no differences
between the conditions or between males and females for the dependent variable d ΄.
d-Prime (Z-CPT)
Figure 12 shows the mean overall vigilance level values (d ΄) for smokers and
nonsmokers during the two conditions for the Z-CPT. A condition x gender ANOVA for
the smoker group during the Z-CPT did not result in any significant main effects or
interactions indicating, no differences between the conditions or between males and
females for the dependent variable d ΄.
A condition x gender ANOVA for the nonsmoker group during the Z-CPT also
did not result in any significant main effects or interactions, indicating no differences
between the conditions or between males and females for the dependent variable d ΄.

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Figure 11: Mean overall d΄ during the DS-APT.

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Figure 12: Mean overall d΄ during the Z-CPT.

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d-Prime (DS-CPT)
Figure 13 shows the mean overall vigilance level values (d ΄) for smokers and
nonsmokers during the two conditions for the DS-CPT. A condition x gender ANOVA
for the smoker group during the DS-CPT revealed a significant main effect for condition
(F [1, 28] = 7.37; p < .01, d = 1.02), indicating that the overall d ΄ level for smokers was
significantly higher during the smoking condition (M = 2.54) compared to the abstinence
condition (M = 2.24) when averaged across gender and a marginally significant condition
x gender interaction (F [1, 28] = 4.0; p < .06, d = .75). To probe the interaction of
condition x gender, interaction contrasts were conducted. The effect of condition
(smoking, abstinence) for each gender were examined and confirmed during the smoking
condition the overall d ΄ levels between male (M = 2.27) and female (M = 2.50) smokers
were not significantly different (p =.42).
A condition x gender ANOVA for the nonsmoker group during the DS-CPT did
not result in any significant main effects or interactions, indicating, no differences
between the two conditions or between males and females for the dependent variable
overall d ΄.
RT (DS-APT)
Figure 14 shows the overall mean reaction time values for the smoker and
nonsmoker groups during the two conditions for the DS-APT. The condition x gender
ANOVA for the smoker group during the DS-APT revealed a main effect of condition (F
[2, 56] = 4.03; p = .05, d = .53) indicating the overall reaction time for smokers was

87
marginally significantly higher during the smoking condition (M = 479.96) compared to
the abstinence condition (M = 508.70) when averaged across gender.
A condition x gender ANOVA for the nonsmoker group during the DS-APT did
not result in any significant main effects or interactions, indicating no differences
between the two conditions or between males and females for the dependent variable
reaction time.
RT (Z-CPT.
Figure 15 shows the overall mean reaction time values for the smoker and
nonsmoker groups during the two conditions for the Z-CPT. A condition x gender
ANOVA for the smoker group during the Z-CPT did not result in any significant main
effects or interactions, indicating no differences between the two conditions or between
males and females for the dependent variable reaction time.
A condition x gender ANOVA for the nonsmoker during the Z-CPT also did not
result in any significant main effects or interactions, indicating no differences between
the two conditions or between males and females for the dependent variable reaction
time.
RT (DS-CPT)
Figure 16 shows the overall mean reaction time values for the smoker and
nonsmoker groups during the two conditions for the DS-CPT. The condition x gender
ANOVA for the smoker group during the DS-CPT revealed a marginal main effect of
condition (F [2, 56] = 4.03; p = .06, d = .53), indicating the overall reaction time for

88
smokers was marginally significantly higher during the smoking condition (M = 502.13
ms) compared to the abstinence condition (M = 524.30 ms) when averaged across gender.
A condition x gender ANOVA for the nonsmoker group during the DS-CPT did
not result in any significant main effects or interactions, indicating no differences
between the two conditions or between males and females for the dependent variable
reaction time.
Beta ( β)
A condition x gender ANOVAs for both smoker and nonsmoker groups during
the DS-APT, the Z-CPT and the DS-CPT did not result in any significant main effects or
interactions indicating no differences between the two conditions or between males and
females for the dependent variable β.
Tests of Facilitation
To test whether nicotine intake enhanced attentional processes beyond that of
nonsmokers a series of t-tests were conducted between the smokers during the smoking
condition and the nonsmokers during the comparable (pseudo-smoking) test for the
dependent variables d ΄ and RT during the DS-APT, Z-CPT and DS-CPT. The smokers
and nonsmokers did not differ in d ΄, or RT, indicating no enhancement following
smoking for the smoker group compared to the pseudo smoking condition of the
nonsmokers.

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Figure 13: Mean overall d΄ during the DS-CPT.

90
Figure 14: Mean overall reaction time during the DS-APT

91
Figure 15: Mean overall reaction time during the Z-CPT.

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Figure 16: Mean overall reaction time during the DS-CPT.

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Discussion
The results of the smoking versus abstinence test sessions in the smoker group
indicated a deficit effect during abstinence on overall vigilance during the DS-APT and
DS-CPT. The effect was evidenced by a reliable decrease in overall d ΄ during the
abstinence test session compared to the ad lib smoking test session, whereas nonsmokers
showed no equivalent change across the three tasks. The results were independent of
changes in response criterion ( β). The results of the smoking versus abstinence test
sessions in the smoker group for the dependent variable overall d ΄ were further supported
by marginally shorter reaction time following smoking during the DS-APT and DS-CPT.
The current results obtained by employing signal detection indices based on
signal detection theory are consistent with previous studies that indicated a deficit in
sustained attention and/or reaction time following smoking abstinence (Edwards et al.,
1985; Gilbert et al., 2000; Lawrence et al., 2002; Mancuso et al., 1999; Parrott & Craig,
1992; Parrott & Winder, 1989; Wesnes & Revell, 1984; Wesnes & Warburton, 1978).
The decreased sensitivity of the smokers during the abstinence condition
compared to the smoking condition during the DS-APT and DS-CPT suggests that
nicotine abstinence affects the early perceptual processing of visual stimuli and not
sustained attention or vigilance. This conclusion is supported both by the lack of nicotine
effect in the Z-CPT that presented clear easily discriminable digits as well as the nicotine
effect in the DS-APT which required a low burden on vigilance due to its self paced
nature. It may be argued that the deficit in sensitivity may be further increased by the fast
pace of the DS-CPT. However, the lack of nicotine effect during the Z-CPT that

94
presented digits at the same 1 per second pace as the DS-CPT suggests there was no
effect of the presentation rate of the digits.
The overall d ΄ results offer further evidence that the degrading of the stimuli in
the DS-APT and DS-CPT require greater and more sustained allocation of attention
resources due to the increased burden on perceptual analysis (Nuechterlein, 1983;
Rissling et al., 2005) compared to the relatively easy recognition that characterizes
clearly discriminable stimuli in most simultaneous discrimination vigilance tasks. The
overall d ΄ results further suggest that the DS-APT and DS-CPT are more sensitive than
clear tasks to the effects of nicotine abstinence due to the specific burden on early visual
processing. This is consistent with the lack of previous studies employing clear stimuli to
report effects of nicotine abstinence or intake (Jacobsen et al., 2005; Michel et al., 1988;
Morris & Gale, 1993; Poltavski & Petros, 2005).
The effect of abstinence on reaction time during the DS-APT and DS-CPT which
present a burden on early visual processing suggests that the speed of processing the
stimuli was slowed following abstinence. The overall d ΄ and reaction time results for the
nonsmoker group indicated similar results following pseudo-smoking and following
pseudo-abstinence, as would be expected.

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Chapter 10
Predictability of behavioral performance by autonomic arousal
Following the Posner and associates neural network model, changes in
alerting/arousal may affect orienting or executive function (see Figure 1). As was
discussed in Chapter 3 autonomic arousal may be measured peripherally by the number
of nonspecific skin conductance responses (NS-SCRs) or the skin conductance level
(SCL). Mixed results have been reported regarding the effects of nicotine intake and
abstinence on autonomic arousal. Autonomic arousal measured as skin conductance level
was reported to increase following smoking and sham smoking (Golding & Mangan,
1982b); as well as during smoking compared to abstinence (Ague, 1974; Karanci, 1985).
Karanci (1985) reported the number of NS-SCRs were higher during smoking than
overnight abstinence. However, Golding and Mangan (1982a) reported that smoking a
middle nicotine delivery cigarette reduced the number of non-specific skin conductance
responses (NS-SCRs) while a low nicotine cigarette and no smoking had no effect. Due
to the mixed results of previous studies further investigation is warranted.
The studies cited in Chapter 3 indicate that measures of tonic or phasic autonomic
arousal have shown promise in predicting performance (Courts, 1942; Freeman, 1940;
Pinneo, 1961). Specific to CPT performance the number of NS-SCRs has been reported
to reliably predict performance when the task causes decreased vigilance (Davies &
Parasuraman, 1982; Munro et al., 1987).

96
Purpose
The secondary analyses were conducted to first determine whether smoking
increased or decreased autonomic arousal compared to abstinence and second to
determine for which type of continuous performance task(s) autonomic arousal measures
are predictive of performance. To accomplish the first goal the autonomic measures of
number of nonspecific skin conductance responses (NS-SCRs) during the passive
attention phase in Experiment 1 and the skin conductance level (SCL) during each CPT
(DS-APT, Z-CPT, DS-CPT) were compared between smoking and abstinence. To
accomplish the second goal the number of NS-SCRs and SCL were tested for their
predictability of performance during the three CPTs.
Predicted Results
Due to the mixed results reported regarding the effect of smoking or abstinence
on autonomic arousal, analyses regarding the change in autonomic arousal were
exploratory.
Regarding the prediction of behavioral performance, it was hypothesized that an
increase in the number of NS-SCRs and SCL would significantly predict increased d ΄
during the DS-APT and the DS-CPT during both the smoking and abstinence conditions
for the smoker group and the pseudo-smoking and pseudo-abstinence conditions for the
nonsmoker group.

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Methods
Participants
Analyses that included the skin conductance variables during the passive attention
task and behavioral data during the three CPTs consisted of a sample of 67 participants
(29 smokers, 38 nonsmokers) for whom data from both analyses were available. Due to
experimental or equipment error during one or more of the three CPTs the data for 16
participants (7 smokers, 9 nonsmokers) were excluded from analyses that included the
dependent variable SCL during the three CPTs due to loss of data. Therefore a total of 51
participants (22 smokers, 29 nonsmokers) were utilized in the regression analyses that
included the dependent variable SCL during the three CPTs. To increase power the linear
regression analyses for the independent variables NS-SCRS and SCL were conducted
separately.
Dependent Variables
The secondary analyses employed included: separate t-tests comparing the
smoking and abstinent conditions for the autonomic variables SCL and NS-SCRs. As
well as separate linear regression analyses for the smoker and nonsmoker groups during
the two conditions and separate linear regression analyses for each CPT. The independent
variables were number of NS-SCRs and SCL. The dependent variables were overall d ′
level during the three CPTs.
NS-SCRs were calculated as the number of nonspecific skin conductance
responses with an amplitude of at least .05 micro Siemens during a scoring window
between 5 and 10 seconds following the passive tones during Experiment 1. SCL was

98
collected during each of the three CPTs (DS-APT, Z-CPT, and DS-CPT). SCL was
calculated as the mean skin conductance level over the course of approximately 5
minutes of each CPT during Experiment 2.
Results
The mean SCL for the smoker and nonsmoker groups for the smoking/pseudo
smoking and abstinence/pseudo abstinence conditions are shown in Figure 17 while the
mean number of NS-SCRs are shown in Figure 18 for the smoker group and Figure 19
for the nonsmoker group. Separate t-tests comparing SCL and number of NS-SCRs were
conducted between the two conditions (smoking, abstinence) for each group separately
did not reveal any significant differences between conditions for either group.
Regression analyses were conducted to test the predictability of SCL and number
of NS-SCRs to behavioral performance separately for each group (smoker, nonsmoker),
each condition (smoking, abstinence) and each CPT (DS-APT, Z-CPT, DS-CPT)
resulting in 24 analyses. For only one analysis was a significant result found. During the
DS-CPT, approximately 10 percent of the variability for overall d ΄ was accounted for by
number of NS-SCRs during the passive orienting task, adjusted R
2
=.096 (F (1, 37) =
5.03, p < .05. Due to the large number of regression analyses the results are within chance
probability.

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Figure 17: Mean number of NS-SCRs during the passive attention phase.

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Figure18: Mean overall SCL during the three CPTs for the smoker group.

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Figure 19: Mean overall SCL during the three CPTs for the nonsmoker group.

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Discussion
The results of the smoking versus abstinence conditions in the smoker group
indicated no differences in autonomic arousal suggesting nicotine had no effect on the
autonomic arousal measures. The results of the smoker group are inconsistent with
previous reports that smoking increased SCL (Ague, 1974; Golding & Mangan, 1982b;
Karanci, 1985). The results are also inconsistent with the previous reports of a decrease in
NS-SCRs (Golding & Mangan, 1982a) or an increase in NS-SCRs (Karanci, 1985)
following smoking compared to overnight abstinence. Due to the mixed results of the
previous studies and the current study the predictability of autonomic measures to
behavioral performance is not promising. As was hypothesized, similar results were
indicated during the pseudo smoking and pseudo abstinence tests for the nonsmoker
group.
The results of the regression analyses indicated neither the NS-SCRs nor the SCL
of the smoker or nonsmoker participants during either condition were predictive of
overall vigilance performance measured as d ΄ during the three CPTs. The results are
inconsistent with the previous studies that reported the number of NS-SCRs to reliably
predict CPT performance when the task results in a decrease in vigilance (Davies &
Parasuraman, 1982; Munro et al., 1987).
Overall the results suggest that the difference in overall d ΄ between the smoking
and abstinence conditions of the smoker group during the DS-APT and DS-CPT
(reported in Chapter 9) were not affected by changes in overall autonomic arousal as
measured by NS-SCRs or SCL. This proposal is supported by the fact that the number of

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NS-SCRs and SCL were not significantly different between the smoking and abstinence
conditions, while the overall d ΄ levels decreased from smoking to abstinence.

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Chapter 11
Methodological Issues
Fundamental methodological limitations exist in the majority of the studies
conducted to test the effects of nicotine intake or abstinence on cognitive or
psychophysiological measures. Therefore, a brief discussion of the possible
methodological limitations of the current two experiments is provided. The specific areas
discussed will include: subject populations, nicotine intake procedures, control measures
and the issue of withdrawal relief or absolute facilitation by nicotine intake.
Use of Smokers
The use of smokers as a subject group may result in certain drawbacks. For
instance smokers are a self-selected group and pre-existing differences between smokers
and nonsmokers may have caused them to begin and continue to smoke. Previous studies
suggest individuals who become smokers differ a priori from individuals who never
become smokers on many characteristics (e.g. type A personality traits, extraversion,
psychoticism, and anger) (Cherry & Kiernan, 1976; Eysenck, 1980; Hartsough &
Lambert, 1987; Seltzer & Oechsli, 1985). Further, daily smokers are never completely
nicotine free. Studies in which smokers are administered a variable dose of nicotine may
be confounded by unknown preexisting plasma nicotine concentrations. As the
physiological and subjective effects of nicotine intake and smoking vary as a function of
degree of habitual nicotine exposure and tolerance, the degree of previous experience
with smoking or other forms of nicotine intake may affect the outcome of results
(Fagerstrom & Schneider, 1989).

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Despite these issues with employing smokers as a subject group, the results
generalize to smokers who are the main interest group in nicotine intake and abstinence
studies. The current two experiments were conducted with young college age smokers.
All smokers smoked at least 10 cigarettes a day. Therefore, although the results may not
generalize to an older more chronic sample of smokers, with a college age sample (mean
age 21.33 years) the effects of nicotine abstinence was evident during the DS-APT and
DS-CPT.
Gender Issues
Gender differences may play a role in the outcome of smoking/nicotine studies.
Gender differences in physiological responsivity to smoking have rarely been assessed in
humans despite a large number of studies in the animal literature showing reliable sex
differences in response to nicotine (see review by Fuxe et al., 1990). Specifically, rat
studies have suggested that females show less up-regulation of brain acetylcholine
receptors in response to chronic nicotine and may metabolize nicotine at a different rate
than males (Koylu, Demirgoren, London, & Pogun, 1997; Kyerematin, Owens,
Chattopadhyay, deBethizy, & Vesell, 1988). Men and women are also shown to differ in
their topography of smoking (Battig, Buzzi, & Nil, 1982; Eissenberg, Adams, Riggins, &
Likness, 1999; Moody, 1980). In general, females take fewer and shorter cigarette puffs,
are less sensitive to some of nicotine’s effects, less successful with nicotine replacement
therapy and more sensitive to smoking cues (Delfino, Jamner, & Whalen, 2001,Woollery,
2003 #372). Although gender was entered in each ANOVA for the smoker and
nonsmoker groups no reliable differences were seen between male and female smokers.

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Facilitation Verses Withdrawal Relief
Early studies have utilized a model in which smoker subjects are tested following
an extended period of abstinence. The abstinence or washout period allows for the
introduction of specific doses of nicotine without the confounding effects of preexisting
nicotine plasma concentrations. This post abstinence test is referred to as a baseline to
which a post smoking or other form of nicotine intake test is compared. Several studies
suggest that any improvement reported compared to baseline is evidence of a facilitating
effect of nicotine (Wesnes & Warburton, 1978, 1983, 1984a, 1984b; Wonnacott, 1990).
This early research has been criticized because the subjects in the studies were
deprived of nicotine for several hours prior to baseline testing. Thus, it is argued that the
baseline data reflect performance under conditions of nicotine withdrawal and that the
improvements in performance were not due to an absolute enhancement of performance
but rather to withdrawal relief (Snyder & Henningfield, 1989; West, 1993). Hughes
(1991) argues two points: First, this design (abstinence for several hours prior to testing)
is somewhat removed from the pharmacological profile of normal smoking, where
several cigarettes are smoked over the course of a day and steady-state blood nicotine
levels may be reached. Second, the design may give a good approximation of the effects
of the first cigarette of the day, but it is difficult to extrapolate the results to any effects
which may be found after repeated nicotine doses.
The current experiments employed a nonsmoker control sample to test whether
nicotine intake by smoking improves the performance of smokers beyond that of
nonsmokers. Although this design may not answer whether nicotine intake by a nicotine

107
naïve individual is facilitating, it answers a more general question of whether smoking
by smokers enhances attention beyond that of nonsmokers. None of the dependent
variables showed an improvement in smokers beyond that of nonsmokers following
smoking in Experiments 1 or 2.
Control of Nicotine Dose
Different brands of cigarettes contain different amounts of nicotine. More
importantly, significant individual variability exists between smokers in plasma nicotine
levels and in the intake of nicotine from a cigarette (Benowitz et al., 1983; Heming,
Jones, & Benowitz, 1987). Therefore, a poor relationship exists between the estimated
nicotine yields of cigarettes and nicotine intake by the smoker. However, it is uncertain
whether smokers have different physiological needs or whether they are attempting to
achieve different physiological effects. The current two experiments used a natural
approach by allowing smokers to smoke ad libitum. Therefore if the smokers required
differing levels of nicotine intake to reach a normal performance level it was not
interrupted during the ad libitum smoking condition.
Ad Lib Smoking
Many studies have employed an ad libitum smoking design where smokers are
allowed to smoke as they wish prior to testing. It has been suggested that when subjects
are not required to abstain from smoking prior to a test session they will attend the
session at their preferred normal nicotine level (Sherwood, Kerr, & Hindmarch, 1989).
The use of tobacco cigarettes to deliver nicotine provides a natural approach. Further, the

108
use of the subjects’ own brand when combined with a within subject design may better
generalize to the environment beyond the laboratory.
The dose of nicotine may vary from subject to subject due to a variation in puff
duration and number as well as differences in brand of cigarette (i.e. low versus high
nicotine yield). Therefore, the time interval between smoking and testing may be
important. The current two experiments involved having smoker subjects smoke 10
minutes prior to testing. By controlling the time before testing the variability in the
latency between intake and testing was minimized. Further, the pharmacokinetics of
nicotine impacts the time frame in which tasks are to be carried out. The subject should
be between the acute effects of the nicotine and the effects of abstinence. It has been
suggested that it is optimal to test a smoker thirty-minutes post-smoking as it qualifies as
‘‘non-deprived” (Pritchard & Robinson, 1998).
The variation in time between intake and testing may account for differences in
results reported or a lack of an effect following nicotine intake. In the current two
experiments smoker subjects were asked to smoke ad libitum prior to testing and again 10
minutes prior to beginning the experiment. This allowed for an approximate 30 minutes
prior to the start of Experiment 1, following consent, set up and instructions, so the
subjects would be non-deprived.
Overnight Abstinence
Overnight abstinence has been employed as an extended abstinence period in
several studies in an attempt to employ a washout period prior to testing. One theoretical
assumption is that the smokers will be in a state of early withdrawal and therefore exhibit

109
differences in measured dependent variables compared to a test following smoking or
other form of nicotine intake. Several studies suggest withdrawal effects can occur after
only 6-12 h of abstinence (Hughes et al., 1990). One important advantage of using an
overnight abstinence is the ability to minimize the discomfort of the smoker and to aid in
compliance as the smoker is normally abstinent during the overnight sleep period.
Therefore, difficulty abstaining is minimized to the morning before testing. The current
two experiments employed an overnight abstinence period to optimize the effects of
abstinence while decreasing the rate of noncompliance and the discomfort level of the
subjects.
Verification of Nicotine Abstinence and Intake
A confirmation of abstinence is important in any design that employs an
abstinence period. The common method is to use a carbon monoxide monitor to test for
abstinence. The normally accepted carbon monoxide level following several hours of
abstinence is below 12 parts per million (PPM). It is believed that anyone with levels
above 12 PPM has not abstained for the prescribed period of time prior to testing
(Pritchard & Robinson, 1998). The current two experiments employed the use of a carbon
monoxide monitor to test for abstinence. No subjects with a CO level above 12 PPM
were tested during the abstinence condition.

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Chapter 12
General Discussion
The general discussion section will be organized around the application of the
results to the neural network model proposed by Posner and associates. As was discussed
in Chapter 1, Posner and associates (Fan & Posner, 2004; Posner et al., 2007; Posner &
Peterson, 1990) propose a neural network model of attention that divides the attention
system into three distinct networks located in three anatomical areas of the brain that are
independently responsible for the three main attentional functions (see Figure 1). One
involves a change of state and is referred to as alerting. The other two, orienting and
executive function, involve the selection and deciphering of stimuli. Experiment 1
employed the psychophysiological indices SCORs, SCDRs and PPI to test which of the
three stages were affected by nicotine intake and its abstinence. Experiment 2 employed
three CPTs that manipulated both the burden on early visual processing and vigilance
demands to test which stage of processing is affected by nicotine intake and its
abstinence. In an attempt to relate the results of experiment 1 and 2 to the neural network
model each attentional process will be discussed separately while the supporting evidence
is introduced.
Orienting
Orienting refers to the selective focusing of perceptual resources on a stimulus.
Passive SCOR magnitude and proportion of responses were employed in Experiment 1 as
physiological indices of the attentional process of orienting. The results of Experiment 1
indicate that although significant orienting occurred during the smoking and abstinence

111
conditions nicotine, did not affect the magnitude or the proportion of responses.
Therefore, the attentional process of orienting as measured by passive SCOR magnitude
and proportion of responses was not affected by nicotine.
In relation to the neural network model the SCDR is related to the blocking out or
filtering of aversive stimuli during the orienting process as changes in SCDR magnitude
indicate a change in a subject’s ability to filter out aversive stimuli. In Experiment 1
passive SCDR magnitude and proportion of responses were employed as a measure of
stimulus filtering or gating. The results of Experiment 1 indicate that although significant
defensive responses had occurred, the magnitude and proportion of responses were not
affected by nicotine.
As was introduced in Chapter 2, PPI is commonly viewed as a measure of
“sensorimotor gating” by which excess or trivial stimuli are screened or “gated out” of
awareness, so that attentional resources may be selectively allocated to salient stimuli.
(Braff & Geyer, 1990; Granholm et al., 1999). Although during selective attention tasks
startle eyeblink modification is modified by controlled attentional processes with greater
inhibition following an attended prepulse than an ignored prepulse, at a 60 ms lead
interval, PPI is not affected by top down attentional modulation (Dawson et al., 1997).
Therefore, in Experiment 1 PPI at the 60 ms lead interval was employed as a
physiological measure of orienting. The results of Experiment 1 suggest that contrary to
the skin conductance measures differences were seen between the smoking and
abstinence conditions at the 60 ms lead interval. Therefore, it is suggested that orienting
when measured at the 60 ms lead interval in this sample was affected by nicotine.

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Executive Function
The attentional process of executive function involves the deciphering of stimuli
as important (target or nontarget) and is influenced by the top down processes involved in
resolving conflict. In Experiment 1 the attentional top down modulation of SCORs during
the active attention phase was employed as a measure of nicotine’s influence on the
executive function process. The results indicating no effect of nicotine intake compared
to abstinence suggest that nicotine had no effect on the executive function process when
measured as the attentional modulation of the SCOR.
A second psychophysiological measure of the executive function process was the
attentional modulation of PPI at the 120 ms lead interval. The results for the attentional
modulation of PPI at 120 ms suggested no effect of nicotine intake compared to
abstinence. However, attentional modulation of PPI at 120 ms was not evidenced in the
smoker sample during either smoking or abstinence or in the nonsmoker group during
comparable tests. Therefore, the results suggest that attentional modulation did not occur;
therefore, whether it was affected by nicotine could not be answered.
In Experiment 2 the effect of nicotine on the executive function process was
tested by employing two tasks (DS-APT, DS-CPT) which placed a burden on the
deciphering of the stimuli by visually degrading the digit stimuli and comparing them to
the Z-CPT which presented highly discriminable clear digit stimuli. The results suggest
that overnight nicotine abstinence results in a decline in the executive function process as
evidenced by poorer sensitivity of the smoker participants (lower d ΄). This proposal is
strengthened by the lack of change from smoking to abstinence in the overall d ′ during

113
the Z-CPT in which clear digits were presented and no burden on executive function
was placed. The differing evidence between the psychophysiological and behavioral
measures may suggest that behavioral measures of the executive function process are
more sensitive to the effects of nicotine intake and abstinence.
Alerting
Alerting is related to how one initiates and maintains an alert state. The
description of alerting is similar to that of arousal. As with alerting, arousal ranges from
sleep to frantic states and changes over the course of the day. In all tasks involving long
periods of processing, as during a CPT, the role of changes of state may be important.
Activation of the alerting system may enhance the orienting and executive
attentional functions by increasing focus allowing for the inhibition of processing of
further stimuli until processing of the original stimulus is complete. Prolonged tasks
requiring vigilance or sustained attention require increased alerting/arousal, which is
difficult to sustain over long periods of time. Therefore alerting decreases may be
expressed by decreased vigilance.
The results of the secondary analyses presented in Chapter 10 suggest that alerting
when measured as autonomic arousal did not differ during the smoking condition
compared to abstinence in the smoker group or between comparable tests in the
nonsmoker group. Moreover, the autonomic arousal measures NS-SCRs and SCL were
not predictive of performance during the three CPTs as measured by overall d ΄ level.
Therefore, in relation to the neural network model of attention the process of
alerting as measured by autonomic arousal did not differ during smoking and abstinence

114
and did not affect the processes of orienting, executive function or vigilance as
measured by overall d ΄ level during the three CPTs.

115
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Zack, M., Belsito, L., Scher, R., Eissenberg, T., & Corrigan, W. A. (2001). Effects of
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Psychopharmacology, 153(2), 249-257.

127
Appendix A: Consent Form Smoker Group
University of Southern California
Department of Psychology

INFORMED CONSENT FOR NON-MEDICAL RESEARCH

CONSENT TO PARTICIPATE IN RESEARCH

Measure of attention during nicotine withdrawal
(Smoker Group)

You are asked to participate in a research study conducted by Anthony J. Rissling, M.A.
and Michael E. Dawson, Ph.D., from the Department of Psychology at the University of
Southern California. This research is part of a dissertation conducted by Anthony J.
Rissling. You were selected as a possible participant in this study because you are aged
18 or older and of your willingness to participate. A total of 100 subjects will be selected
from undergraduate psychology classes to participate. Your participation is voluntary.
You should read the information below, and ask questions about anything you do not
understand, before deciding whether or not to participate.

PURPOSE OF THE STUDY
The purpose of the present study is to measure the effects of nicotine intake and nicotine
abstinence on early visual processing, sustained attention and orienting.

PROCEDURES
If you volunteer to participate in this study, we would ask you to do the following things:

1) Complete two (one hour) experimental sessions approximately one week apart.
2) On one experimental session you will be asked to abstain from smoking
beginning at 9:00 PM the night before the experimental session until the
experimental session is completed the following morning. (total time of
abstinence approx. 12 hrs).
3) On a second experimental session you will be asked to complete the same
attention and orienting tasks but will not be asked to abstain from smoking.
4) Complete a form regarding medication use, alcohol consumption, smoking and
health history.
5) After a short introduction the experimenter will attach small sensors on the end of
your index and middle finger of your non-dominant hand. The sensors will
measure your physiological responses to stimuli that you will see and hear. These
sensors rest on the surface of your skin and will not affect or harm you in any
way.

128
6) Complete a quick test of visual acuity.
7) Press a button every time you see a zero on a computer screen.
8) You will hear a series of random tones to which you do not need to respond.
9) You will have the carbon monoxide levels in your breath measured by blowing
into a carbon monoxide monitor. Smoking causes carbon monoxide levels in a
persons blood to rise. Therefore carbon monoxide levels are commonly used to
measure decreased smoking. The levels will be used in this study to indicate
decreased smoking during the nicotine withdrawal session compared to the
session where you will smoke as per usual.
10) You will be monitored by a closed circuit video monitor both for your safety and
to detect movement during the experiment. However, the video will not be
recorded.

Each of two experimental sessions will last approximately 60 minutes (total 2 hours).
This experiment will be conducted in SGM 907.

POTENTIAL RISKS AND DISCOMFORTS
The risks associated with this study are minimal. Although the static-like noises are loud,
they are very brief and pose no risk to your hearing. You may experience slight irritation
or reddening of the skin due to the sensors. This will go away after the sensors are
removed. You may experience discomfort during the nicotine withdrawal phase of the
experiment. Symptoms of nicotine withdrawal often occur within the six to 12 hours.
Common side effects may include: nicotine cravings, difficulty concentrating, irritability,
anxiety or headache. This is minimized by having you abstain from smoking overnight;
therefore discomfort may only be experienced during the morning prior to testing. When
the testing session is complete you may smoke as per usual.

POTENTIAL BENEFITS TO SUBJECTS AND/OR TO SOCIETY
You may not directly benefit from participating in this study. The knowledge gained may
enhance our understanding of the affects of nicotine intake and abstinence on early visual
processing and the skin conductance orienting response. At the conclusion of the study if
you are interested in the results you may email Michael Dawson at mdawson@usc.edu or
Anthony Rissling at rissling@usc.edu to receive a summary of our findings. The
approximate time to complete the study and analysis is one year.

PAYMENT/COMPENSATION FOR PARTICIPATION
You will receive two hours of extra credit to the psychology course of your choice, which
allows extra credit for participation in research studies. Further, you will be paid $5.00 at
the completion of each of the experimental sessions. If you are not receiving extra credit,
you will receive $30.00 at the completion of each of the experimental sessions.

129
CONFIDENTIALITY
Any information that is obtained in connection with this study and that can be identified
with you will remain confidential and will be disclosed only with your permission or as
required by law. You will be identified only by a unique subject number.

The data you provide will be stored in cabinets and on computers within the human
psychophysiology laboratory and offices. These cabinets are not locked and the
computers are not password protected, however, they are kept in rooms that are locked
unless someone is working inside and are double locked during non-work hours. On-line
access to the computers to the computers is password protected. Only members of this
research team have access to these files and computers.

The recording of your physiological reactions will be retained for possible re-analysis
until no longer considered useful. At this time the computer files will be deleted or erased
and paper records will be destroyed.

When the results of the research are published or discussed at conferences no information
will be included that would reveal your identity. Your data will be shared only with
members of this research team.
During this experiment we will monitor you with a video camera from an adjacent room
but this will not be recorded. The purpose of monitoring is to detect movements that may
interfere with the physiological recordings.

PARTICIPATION AND WITHDRAWAL
Your participation in this study is completely voluntary. If you volunteer to be in this
study, you may withdraw at any time without consequences of any kind. You may also
refuse to answer any questions you don’t want to answer and still remain in the study.
The investigator may withdraw you from this research if circumstances arise which
warrant doing so. Some instances may include: equipment malfunction, uncorrected sight
or hearing impairment. If you or the experimenter decides not to continue the
experimental session you will receive your full credit for the test session and the financial
compensation ($5.00 Psychology subject pool participants) ($30.00 Student population
not participating in the Psychology Subject Pool).

ALTERNATIVES TO PARTICIPATION
One alternative is to not participate. You may earn credit for the Psychology Student
Subject Pool by completing a different study. In addition, the professors may provide
alternative bonus point earning activities for those who cannot participate (due to ill
health or other limiting conditions) or for those who do not wish to participate in
experiments. Please see your instructor or the Subject Pool supervisor for more
information about these other options.

130

IDENTIFICATION OF INVESTIGATORS
If you have any questions or concerns about the research, please feel free to contact:
Michael E. Dawson, Ph.D. at (213) 740-2294 or Anthony J. Rissling (213) 740-2297,
Dept. of Psychology, SGM 501, Los Angeles, CA 90089-1061.

RIGHTS OF RESEARCH SUBJECTS
You may withdraw your consent at any time and discontinue participation without
penalty. You are not waiving any legal claims, rights or remedies because of your
participation in this research study. If you have questions regarding your rights as a
research subject, contact the University Park IRB, 827 Downey Way, Stonier Hall, Room
224a, Los Angeles, CA 90089-1695, (213) 821-5272 or upirb@usc.edu.

SIGNATURE OF RESEARCH SUBJECT

I understand the procedures described above. My questions have been answered to my
satisfaction, and I agree to participate in this study. I have been given a copy of this
form.

Name of Subject

Signature of Subject Date

SIGNATURE OF INVESTIGATOR

I have explained the research to the subject and answered all of his/her questions. I
believe that he/she understands the information described in this document and freely
consents to participate.

Name of Investigator

Signature of Investigator Date (must be the same as subject’s)

131
Appendix B: Consent Form Nonsmoker Group
University of Southern California
Department of Psychology

INFORMED CONSENT FOR NON-MEDICAL RESEARCH

CONSENT TO PARTICIPATE IN RESEARCH

Measure of attention during nicotine withdrawal
(Non-Smoker Group)

You are asked to participate in a research study conducted by Anthony J. Rissling, M.A.
and Michael E. Dawson, Ph.D., from the Department of Psychology at the University of
Southern California. This research is part of a dissertation conducted by Anthony J.
Rissling. You were selected as a possible participant in this study because of your
willingness to participate and you are aged 18 or older. A total of 100 subjects will be
selected from undergraduate psychology classes to participate. Your participation is
voluntary. You should read the information below, and ask questions about anything you
do not understand, before deciding whether or not to participate.

PURPOSE OF THE STUDY
The purpose of the present study is to measure the effects of nicotine intake and nicotine
abstinence on early visual processing, sustained attention and orienting.

PROCEDURES
If you volunteer to participate in this study, we would ask you to do the following things:

11) Complete two (one hour) experimental sessions approximately one week apart.
12) Complete a form regarding medication use, alcohol consumption, smoking and
health history.
13) After a short introduction the experimenter will attach small sensors on the end of
your index and middle finger of your non-dominant hand. The sensors will
measure your physiological responses to stimuli that you will see and hear. These
sensors rest on the surface of your skin and will not affect or harm you in any
way.
14) Complete a quick test of visual acuity.
15) Press a button every time you see a zero on a computer screen.
16) You will hear a series of random tones to which you do not need to respond.
17) You will be monitored by a closed circuit video monitor both for your safety and
to detect movement during the experiment. However, the video will not be
recorded.

132

Each of two experimental sessions will last approximately 60 minutes (total 2 hours).
This experiment will be conducted in SGM 907.

POTENTIAL RISKS AND DISCOMFORTS
The risks associated with this study are minimal. Although the static-like noises are loud,
they are very brief and pose no risk to your hearing. You may experience slight irritation
or reddening of the skin due to the sensors. This will go away after the sensors are
removed.

POTENTIAL BENEFITS TO SUBJECTS AND/OR TO SOCIETY
You may not directly benefit from participating in this study. The knowledge gained will
enhance our understanding of the affects of nicotine intake and abstinence on early visual
processing and the skin conductance orienting response. At the conclusion of the study if
you are interested in the results you may email Michael Dawson at mdawson@usc.edu or
Anthony Rissling at rissling@usc.edu to receive a summary of our findings. The
approximate time to complete the study and analysis is one year.

PAYMENT/COMPENSATION FOR PARTICIPATION
You will receive two hours of extra credit to the psychology course of your choice, which
allows extra credit for participation in research studies. Further, you will be paid $5.00 at
the completion of each of the experimental sessions. If you are not receiving extra credit
for a psychology course you will receive $10.00 at the completion of each of the
experimental sessions.

CONFIDENTIALITY
Any information that is obtained in connection with this study and that can be identified
with you will remain confidential and will be disclosed only with your permission or as
required by law. You will be identified only by a unique subject number.

The data you provide will be stored in cabinets and on computers within the human
psychophysiology laboratory and offices. These cabinets are not locked and the
computers are not password protected, however, they are kept in rooms that are locked
unless someone is working inside and are double locked during non-work hours. On-line
access to the computers to the computers is password protected. Only members of this
research team have access to these files and computers.

The recording of your physiological reactions will be retained for possible re-analysis
until no longer considered useful. At this time the computer files will be deleted or erased
and paper records will be destroyed.

When the results of the research are published or discussed at conferences no information
will be included that would reveal your identity. Your data will be shared only with
members of this research team.

133

During this experiment we will monitor you with a video camera from an adjacent room
but this will not be recorded. The purpose of monitoring is to detect movements that may
interfere with the physiological recordings.

PARTICIPATION AND WITHDRAWAL
Your participation in this study is completely voluntary. If you volunteer to be in this
study, you may withdraw at any time without consequences of any kind. You may also
refuse to answer any questions you don’t want to answer and still remain in the study.
The investigator may withdraw you from this research if circumstances arise which
warrant doing so. Some instances may include: equipment malfunction, uncorrected sight
or hearing impairment. If you or the experimenter decides not to continue the
experimental session you will receive your full credit for the test session and the financial
compensation ($5.00 Psychology Subject Pool Participants) ($10.00 Student population
not participating in the Psychology Subject Pool).

ALTERNATIVES TO PARTICIPATION
One alternative is to not participate. You may earn credit for the Psychology Student
Subject Pool by completing a different study. In addition, the professors may provide
alternative bonus point earning activities for those who cannot participate (due to ill
health or other limiting conditions) or for those who do not wish to participate in
experiments. Please see your instructor or the Subject Pool supervisor for more
information about these other options.

IDENTIFICATION OF INVESTIGATORS
If you have any questions or concerns about the research, please feel free to contact:
Michael E. Dawson, Ph.D. at (213) 740-2294 or Anthony J. Rissling (213) 740-2297,
Dept. of Psychology, SGM 501, Los Angeles, CA 90089-1061.

RIGHTS OF RESEARCH SUBJECTS
You may withdraw your consent at any time and discontinue participation without
penalty. You are not waiving any legal claims, rights or remedies because of your
participation in this research study. If you have questions regarding your rights as a
research subject, contact the University Park IRB, 827 Downey Way, Stonier Hall, Room
224a, Los Angeles, CA 90089-1695, (213) 821-5272 or upirb@usc.edu.

134

SIGNATURE OF RESEARCH SUBJECT

I understand the procedures described above. My questions have been answered to my
satisfaction, and I agree to participate in this study. I have been given a copy of this
form.

Name of Subject

Signature of Subject Date

SIGNATURE OF INVESTIGATOR

I have explained the research to the subject and answered all of his/her questions. I
believe that he/she understands the information described in this document and freely
consents to participate.

Name of Investigator

Signature of Investigator Date (must be the same as subject’s)

135
Appendix C: Medication and Health History Form
SUBJECT # ____________

Please answer the following questions to the best of your ability.
Demographics
Male ______ Female _______

Date of Birth ________

Right Handed _______ Left Handed ________

Alcohol Consumption

When was the last time you consumed any alcohol? ________________

If so how much ____________

Average # of drinks per week ____________

Average # of drinks per month ___________

Are you currently taking any medications? ________

Please specify ________________ Last taken _______________ Dosage ____________

Smoking / Nicotine
Do you smoke? ____________

If so please specify the average amount per day _________________

Time of last smoke _____________

How long have you smoked cigarettes ? Years ______ Months _______

Have you attempted to quit smoking in the past 6 months? Yes ____ No _____

136
Please rate your current craving for a cigarette (Circle one)

0 1 2 3 4 5 6 7 8 9 10
Street Drugs

Have you ever taken any drugs? ( i.e. Marijuana, Cocaine)
Yes ______ No ______
If yes please specify __________________________________________________
When was the last time? _____________

Sleep

How many hours of sleep did you get last night? ____________

Vision
Do you wear glasses for reading or vision? _________

Reading Yes _____ No ______
Distance Yes _____ No ______

Do you have any problems with your vision?

Yes ______ No ______ If yes please specify _____________________________
Hearing

Do you have any problems with your hearing? Yes ____ No ____
If yes please specify _____________________________________
Health
Have you been diagnosed with any of the following disorders? (Check any that apply)

137
Diabetes _______ Depression _______
Alcohol Dependence _______ Bipolar Disorder (Manic Depression) ______
Head Injury (with unconsciousness)
_____
Drug Dependence _______
Post Traumatic Stress Disorder
_______
Attention Deficit Hyperactivity Disorder
_______
Heart Disease _______ Attention Deficit Disorder ______

Have any members of your family been diagnosed with any of the above conditions?
Yes ____ No _____
If yes please specify _________________________________________.

138
Appendix D: Fagerstrom Tolerance Questionnaire
Write the number of the answer that is most applicable on the line to the left of the
question.

______1. How soon after you awake do you smoke your first cigarette?
0. After 30 minutes
1. Within 30 minutes

______2. Do you find it difficult to refrain from smoking in places where it is forbidden,
such as the library, theater, or doctors' office?
0. No
1. Yes

______3. Which of all the cigarettes you smoke in a day is the most satisfying?
0. Any other than the first one in the morning
1. The first one in the morning

______4. How many cigarettes a day do you smoke?
0. 1-15
1. 16-25
2. More than 26

______5. Do you smoke more during the morning than during the rest of the day?
0. No
1. Yes

______6. Do you smoke when you are so ill that you are in bed most of the day?
0. No
1. Yes

______7. Does the brand you smoke have a low, medium, or high nicotine content?
0. Low
1. Medium
2. High

______8. How often do you inhale the smoke from your cigarette?
0. Never
1. Sometimes
2. Always

Abstract (if available)

Abstract Following the neural network model of attention proposed by Posner and associates two experiments were conducted. Student smokers were tested following smoking and overnight abstinence to measure the effects of smoking on the specific processes of attention (orienting, executive function, alerting). A group of nonsmokers was tested twice without nicotine manipulation. During Experiment 1 the two psychophysiological indices of attention, skin conductance orienting response and prepulse inhibition of the startle eyeblink reflex were employed to test the effects of nicotine on the attentional processes of orienting and executive function. No effect of smoking was evidenced compared to abstinence on the psychophysiological measures. The results of Experiment 1 indicated smoking did not affect the processes of orienting or executive function when measured by the two psychophysiological indices. Nonsmoker responses did not differ between comparable tests following continued abstinence. During Experiment 2 three continuous performance tasks were employed that manipulated the burden on early visual processing and vigilance to test the effects of nicotine on these functions.

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Asset Metadata

Creator Rissling, Anthony Joseph (author)

Core Title Effects of nicotine abstinence on orienting, executive function, arousal and vigilance

School College of Letters, Arts and Sciences

Degree Doctor of Philosophy

Degree Program Psychology

Publication Date 04/16/2008

Defense Date 03/28/2008

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag attention,continuous performance tests,OAI-PMH Harvest,skin conductance,startle eyeblink

Language English

Advisor Dawson, Michael E. (committee chair), John, Richard S. (committee member), McClure, William O. (committee member), Schell, Anne M. (committee member), Walsh, David A. (committee member)

Creator Email rissling@usc.edu

Permanent Link (DOI) https://doi.org/10.25549/usctheses-m1138

Unique identifier UC173943

Identifier etd-Rissling-20080416 (filename),usctheses-m40 (legacy collection record id),usctheses-c127-58833 (legacy record id),usctheses-m1138 (legacy record id)

Legacy Identifier etd-Rissling-20080416.pdf

Dmrecord 58833

Document Type Dissertation

Rights Rissling, Anthony Joseph

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Repository Name Libraries, University of Southern California

Repository Location Los Angeles, California

Repository Email cisadmin@lib.usc.edu