Spatiotemporal receptive field structure of neurons in the lateral geniculate nucleus of binocularly deprived cats

Abstract

Twelve cats were binocularly deprived of pattern vision from the time of eye opening by rearing in masks. Six cats were raised in masks for 5 to 7 months until an acute experiment (group D) and 6 others were additionally trained in visual pattern discrimination for 2 to 5 months following the initial deprivation period (group DV). In all cats the receptive fields (RFs) of neurons in lateral geniculate nucleus were analyzed with three-dimensional computer plots (response planes). The percentage of neurons encountered with homogeneous RFs (Y cells) was 7 perecent in D cats and 16 percent in DV cats. Both values are much lower than in normal cats. Y-type neurons had weakly developed surrounds of their RFs and more phasic responses than normal. Surrounds of heterogeneous (X cell) RFs were also weak or absent. X-type receptive field centers were enlarged in both D and DV animals when compared to a sample from normal cats. They were also larger in D than in DV cats, particularly within 8 degrees of eccentricity. The late components of the response patterns of X cells were weak or absent. Seven percent of neurons found in the middle of the A laminae in DV cats had an atypical (ON-OFF like) structure of their receptive field which might indicate that they were like immature X or Y neurons.