The Contributions of Visual Information to Reaching Behaviors
Open Access
- Author:
- Shabbott, Britne Anne
- Graduate Program:
- Neuroscience
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- December 19, 2008
- Committee Members:
- Robert L Sainburg, Dissertation Advisor/Co-Advisor
Robert L Sainburg, Committee Chair/Co-Chair
Dagmar Sternad, Committee Member
Byron C Jones, Committee Member
Jinger Gottschall, Committee Member
Jonathan T Mordkoff, Committee Member - Keywords:
- motor control
visuomotor adaptation
movement
handedness
online control - Abstract:
- Vision is one of the more salient sources of information that contributes to both the planning and the execution of many reaching behaviors. In fact, the contributions of vision to reaching accuracy were first described over a century ago in a seminal monograph by Woodworth (1899), which differentiated between the use of vision for planning and for on-line corrections. Today, this distinction remains a central issue in the study of sensory contributions to movement. Some evidence has suggested that the differences in performance between limbs results from specialization of the dominant hemisphere for visual-mediated correction processes, although results from empirical studies are inconsistent. Additionally, the way in which visual information is used for planning and on-line corrections, within a limb, remains largely unknown. Thus, the experiments presented in this dissertation were designed to 1) determine whether handedness emerges as a result of more efficient or faster visual feedback processing in the dominant hemisphere, 2) examine what aspects of visual error information mediate on-line corrections within a limb, and 3) investigate how sensory information that is detected during the course of motion is used to update planning of subsequent movements, as occurs during visual-motor adaptation. The results of these experiments revealed that dominant arm performance advantages during reaching are not dependent on visual-mediated correction processes, but instead reflect the predictions of the “dynamic dominance” hypothesis. This hypothesis proposes that the non-dominant and dominant limb/hemisphere systems have become specialized for controlling limb impedance and task dynamics, respectively. We also provide evidence that visual-based corrections that occur within- and between-trials are qualitatively different, and thus, use visual information differently. However, sensory information provided within-trials was shown to be crucial for visuomotor adaptation. Collectively, the results of these studies improve our understanding of how visual information is used during reaching behaviors, which may have implications for neural disorders and disease.