Faculty Proceedings, Presentations, Posters, Speeches, Lectures, etc.
Title
Directional Bias of Neurons In Visual Area 2 (V2) of Monkeys Reared With Early Strabismus
Format
Poster
ISBN or ISSN
0146-0404
Conference Title
Association for Research in Vision and Ophthalmology Annual Meeting
Organization/Association/Group
Association for Research in Vision and Ophthalmology
Publication Title
Investigative Ophthalmology and Vision Science
Volume
43
Issue
13
Publication Date / Copyright Date
12-1-2002
First Page
4775
Publisher
Association for Research in Vision and Ophthalmology
Abstract
Purpose:Humans and monkeys with early strabismus are known to exhibit monocular naso-temporal asymmetries in pursuit eye movements and visual tracking, similar to those found in normal neonates. To gain insight into the neural basis for these oculomotor asymmetries, we investigated the directional bias of neurons in cortical areas V1 and V2 of strabismic monkeys. Methods:Unilateral convergent misalignment was surgically induced in five infant monkeys at 4 weeks of age. The monkeys were reared in a normally lighted visual environment and behavioral testing to measure their monocular and binocular capacities were conducted between 2 and 4 years of age. Upon completion of the behavioral testing, we conducted extracellular single-unit recording experiments under anesthesia and paralysis in which we assessed the directional bias of individual V2 neurons (N=323) using a vector summation method. Results:We did not find an overabundance of V2 units preferring the temporal to nasal direction of stimulus drift. Instead, we found that the overall directional bias of V2 units was significantly reduced in strabismic monkeys compared to that in normal monkeys. These reductions were slightly larger for those units dominated by the behaviorally amblyopic eye. Comparable deficits in directional bias were also found for V1 neurons in these monkeys. Conclusion:Our results suggest that the oculomotor asymmetries in strabismic monkeys are not due to asymmetries in the directional properties of V1 or V2 neurons, but rather due to very impoverished cortical control over the brain stem nuclei that initiate eye movements.
Disciplines
Optometry
Keywords
visual cortex, strabismus, electrophysiology, non-clinical
NSUWorks Citation
Sakai, Eiichi; Mori, Takafumi; Zhang, Bin; Bi, Hua; Smith, Earl L. III; and Chino, Yuzo M., "Directional Bias of Neurons In Visual Area 2 (V2) of Monkeys Reared With Early Strabismus" (2002). Faculty Proceedings, Presentations, Posters, Speeches, Lectures, etc.. 58.
https://nsuworks.nova.edu/hpd_opt_facpres/58
