Journal of Neuroscience, Vol 8, 2507-2516, Copyright © 1988 by Society for Neuroscience
Binocularly deprived cats: binocular tests of cortical cells show regular patterns of interaction
I Ohzawa and RD Freeman
Group in Neurobiology, University of California, Berkeley 94720.
If an animal is prevented from receiving visual experience during an early
developmental phase, pronounced dysfunctions are observed. Physiological
tests reveal gross abnormalities in the striate cortex. Cells in visual
cortex are either unresponsive of their response characteristics are
erratic. Although fewer than normal numbers of binocular cells are found in
cats reared with binocular lid suture, a population remains that can be
activated by stimulation through either eye. We have studied cortical cells
in binocularly deprived cats in order to specify monocular and binocular
response characteristics. The primary hypothesis we have examined is that
the abnormal response properties of these cells are a result of an
irregular structure or substructure of the receptive fields. Kittens were
binocularly lid- sutured soon after birth, and were studied physiologically
at ages between 7 and 11 months. Standard techniques were used to record
from single cells in striate cortex. Drifting gratings were presented to
either eye or to both eyes together. In the latter case, the relative
interocular phase was varied between the gratings so that the retinal
disparity of the stimuli was changed. We confirmed the expected finding
that most cells were either unresponsive or erratic in their response. Of
the cells that responded, monocular tuning functions for orientation and
spatial frequency of the stimulus were often irregular. However, even in
these cases, binocular interaction patterns of cortical responses were
nearly always highly regular and displayed phase- specific profiles. A
model is presented that explains this finding and suggests how binocular
deprivation may result in disorganized receptive- field structure.