DEVELOPMENT OF INHIBITORY MECHANISMS IN THE KITTENS VISUAL-CORTEX

The objective of this study was to evaluate the maturity of three inhi bitory mechanisms (end-inhibition, side-inhibition, and cross-orientat ion inhibition) in the striate cortex of kittens at 4 weeks postnatal. To accomplish this, we made extracellular recordings from area 17 neu rons while presenting visual stimuli consisting of sinusoidal luminanc e gratings or composites of gratings, We then compared data from kitte ns relating to various characteristics of each inhibitory mechanism wi th data from adults. We find that end-inhibition, side-inhibition, and cross-orientation inhibition are all present in kittens, and all show signs of maturity by 4 weeks postnatal. We conclude that the developm ent of these inhibitory mechanisms occurs relatively early, and may co incide with the development of excitatory properties.