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Title page for ETD etd-07102008-203016


Type of Document Master's Thesis
Author Cao, Shen
Author's Email Address ucaoshen@gmail.com
URN etd-07102008-203016
Title Modulation of free viewing and saccades on visual cortex
Degree Master of Arts
Department Psychology
Advisory Committee
Advisor Name Title
Anna Roe Committee Chair
Vivien Casagrande Committee Member
Keywords
  • Visual cortex -- Physiology
  • Free Viewing
  • Saccade
  • Expectation
  • Time Course
  • Functional Domain
  • Optical Imaging
  • Visual perception
  • Saccadic eye movements
Date of Defense 2008-07-10
Availability unrestricted
Abstract
In visual science research, awake animals traditionally are required to perform simple fixation tasks. Fixation can indeed simplify the situation because the spatial relationship between the visual objects and the retina is unchanged, and no obvious eye movement is made. But in real life, animals are freely viewing, and their center of gaze continually jumps. Studies suggest that the visual system might use a different information-processing pattern under natural viewing conditions. Here with optical imaging of intrinsic signals, we studied neural activity of macaque V1, V2 and V4 under fixation, free viewing and guided saccades conditions. We found: (1) that compared with fixation, functional domain distribution remained unchanged in V1, V2 and V4 during free viewing and guided saccades; (2) that neural activity in visual cortical areas V1, V2 and V4 was suppressed under guided saccades, compared with both fixation and free viewing. Another phenomenon we observed was that optical imaging signal during the beginning one to two seconds after the stimulus onset was affected by neither stimulus presentation nor eye movement, but very possibly the animal’s expectation. These findings suggest avenues for future research though the mechanisms for these three phenomena are unclear.
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