Journal of Neurophysiology, Vol 64, Issue 4 1352-1360, Copyright © 1990 by APS
Interocular torsional disparity and visual cortical development in the cat
M. R. Isley, D. C. Rogers-Ramachandran and P. G. Shinkman
Department of Psychology and Biological Sciences Research Center, University of North Carolina, Chapel Hill 27599.
1. The present experiments were designed to assess the effects of
relatively large optically induced interocular torsional disparities on the
developing kitten visual cortex. Kittens were reared with restricted visual
experience. Three groups viewed a normal visual environment through goggles
fitted with small prisms that introduced torsional disparities between the
left and right eyes' visual fields, equal but opposite in the two eyes.
Kittens in the +32 degrees goggle rearing condition experienced a 16
degrees counterclockwise rotation of the left visual field and a 16 degrees
clockwise rotation of the right visual field; in the -32 degrees goggle
condition the rotations were clockwise in the left eye and counterclockwise
in the right. In the control (0 degree) goggle condition, the prisms did
not rotate the visual fields. Three additional groups viewed high-contrast
square-wave gratings through Polaroid filters arranged to provide a
constant 32 degrees of interocular orientation disparity. 2. Recordings
were made from neurons in visual cortex around the border of areas 17 and
18 in all kittens. Development of cortical ocular dominance columns was
severely disrupted in all the experimental (rotated) rearing conditions.
Most cells were classified in the extreme ocular dominance categories 1, 2,
6, and 7. Development of the system of orientation columns was also
affected: among the relatively few cells with oriented receptive fields in
both eyes, the distributions of interocular disparities in preferred
stimulus orientation were centered near 0 degree but showed significantly
larger variances than in the control condition.(ABSTRACT TRUNCATED AT 250
WORDS)
