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HEMISPHERIC SPECIALIZATION OF REACH-TO-GRASP ACTIONS
by
Jarugool Tretriluxana
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
(BIOKINESIOLOGY)
May 2008
Copyright 2008 Jarugool Tretriluxana
Object Description
| Title | Hemispheric specialization of reach-to-grasp actions |
| Author | Tretriluxana, Jarugool |
| Author email | tretrilu@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Biokinesiology & Physical Therapy |
| School | Independent Health Professions |
| Date defended/completed | 2007-06-01 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-01-28 |
| Advisor (committee chair) | Winstein, Carolee J. |
| Advisor (committee member) |
Gordon, James Schweighofer, Nicolas Azen, Stanley Arbib, Michael A. |
| Abstract | This dissertation was designed to determine the unique contribution of each hemisphere to the control of reach-to-grasp actions. In particular the three studies are focused on two fundamental aspects of movement that together are essential for efficient and successful performance: the visuo-motor transformation for grasp pre-shaping and transport-grasp coordination between arm and hand movements.; Twenty four participants with stroke and twelve age-matched non-disabled individuals were recruited. All volunteers were right hand dominant. Participants with stroke used the ipsilesional hand and non-disabled controls used each hand to perform rapid reach-to-grasp actions under three experimental manipulations. In Experiment 1, three object sizes were used as a task constraint for grasp. In Experiment 2, a barrier between the hand's starting position and the object to be grasped was used as a task constraint for hand path. In Experiment 3, the barrier condition was followed immediately by a no barrier condition to examine the persistence of the adaptive response. Kinematics measures were used to characterize grasp pre-shaping and transport-grasp coordination for participant groups, and task conditions.; For non-disabled participants, manual asymmetries were identified by manipulating task constraints for grasp: the left hand exhibited an earlier response for aperture pre-shaping, whereas the right hand demonstrated a stronger coordinated control of hand reaching and finger grasping. To untangle hemispheric specialization from hand dominance, corresponding experiments were conducted with individuals after unilateral brain damage. In the first of these experiments, the left hemisphere damage group showed an impairment of grasp pre-shaping and the right hemisphere damage group demonstrated weaker transport-grasp coordination compared to matched non-disabled counterparts. This grasp impairment was dependent on lesion location, with the most profound impairment observed in the case with a left anterior intra-parietal lesion. Further, the right hemisphere specific impairment, i.e. weaker transport-grasp coordination was magnified in Experiment 2 that manipulated transport path with a barrier. In Experiment 3, after exposure to the barrier condition, the curved hand path and the weaker transport-grasp coordination persisted only for the group with right hemisphere damage.; Overall, the results of these experiments provides strong evidence of hemispheric specialization in the control of automatic reach-to grasp actions: the left hemisphere appears to be specialized in the visuo-motor transformation for grasp pre-shaping whereas the right hemisphere appears to be more specialized for transport-grasp coordination. In addition to these hemisphere specific impairments, another type of abnormal motor behavior termed 'hyperfunction' was evident through comparison of the performance between the stroke and non-disabled groups. Specifically, transport-grasp coordination was stronger after left hemisphere damage and anticipatory grasp pre-shaping occurred earlier after right hemisphere damage, compared to that of the non-disabled group. One viable interpretation of this hyperfunction is that the stroke lesion acts to disinhibit the non-lesioned hemisphere, thereby allowing expression of the specialized contribution from the non-lesioned hemisphere. To further test this hypothesis and investigate the mechanism and the locus for hemispheric specialization of reach-to-grasp actions, transcranial magnetic stimulation studies are planed. |
| Keyword | hemispheric specialization; reach-to-grasp kinematics; dexterity; object avoidance; ipsilesional hand; stroke |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m994 |
| Contributing entity | University of Southern California |
| Rights | Tretriluxana, Jarugool |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-TretriluxanaJ-20080128 |
| Archival file | uscthesesreloadpub_Volume51/etd-TretriluxanaJ-20080128.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | HEMISPHERIC SPECIALIZATION OF REACH-TO-GRASP ACTIONS by Jarugool Tretriluxana 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 (BIOKINESIOLOGY) May 2008 Copyright 2008 Jarugool Tretriluxana |
