The Electrophysiology of Human Visuomotor Integration During Memory-Guided Action

• Author / Creator

  Cruikshank, Leanna C

• The visuomotor pathways of the brain are comprised of millions of neurons and complex
  interconnections among them exist. In order to fully understand visuomotor processes, we needto understand the mechanisms that allow neurons within these areas and between networks to coordinate with each other. The objective of the four studies presented in this thesis was to test
  whether specific electrophysiological signals reflect visuomotor integration and determine which aspects of behaviour are reflected in the modulation of these signals. I measured oscillatory and ERP activity during various delayed action tasks in order to determine how the brain uses both immediate visual information and visuoperceptual memory to execute goal-directed reaching. In the first study I addressed whether visuomotor regions might coordinate their function
  via theta oscillations. I determined that theta synchronization and mu desynchronization may represent broadly applicable rhythmic mechanisms for integration and visuomotor function in the human brain. In the second study, I investigated event-related potentials (ERPs) during the planning phase of actions. I found that the N170 ERP component, which is generally considered in the context of perception, is also sensitive to elements of action planning and connects visual perceptual and action processes. In the third study, I expanded on these results and investigated how perception for action is coded over time, by manipulating the delay period of the task. As delay period between target occlusion and movement initiation increased, modulation in the N170 amplitude reflected the accuracy of the stored memory representation. Finally, in the fourth study, I investigated how the two hemispheres of the brain contribute to visuomotor processes using the N170 as a measure. Results suggest that whereas visually initiated action is left-dominant, memory-initiated action may be right-dominant. In sum, this body of work provides further insight into the electrophysiological basis of human visuomotor function. Employment of a modifiable reaching paradigm has permitted the systematic investigation of how immediate available visual information and visuoperceptual memory informs action. I have identified two signals that can be used to assess brain activity during visuomotor behaviour in real-time.

• Subjects / Keywords

  • Delayed action
  • N170 ERP
  • Memory-guided action
  • Perception
  • Theta

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3KD1QS33

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.