[Changes in the receptive fields of cat lateral geniculate body neurons following removal of corticofugal influence].

The number of spikes in responses of the lateral geniculate neurons increased after section of ipsilateral corticogeniculate connections. The operation caused a distinct intensification of lateral inhibition effects in the operated side. Zones of complete spatial summation in the receptive fields of neurons in the operated side changed according to the contrast of the used light stimuli. It is suggested that corticogeniculate influences are of inhibitory nature and that receptive fields possessing a changing zone of spatial summation are realized by intrageniculate mechanisms.