[Reactions of neurons of the reticular and ventral anterior thalamic nuclei of the cat to electric stimulation of the relay nuclei of the optic thalamus].

Responses of 92 reticular (R) and 105 ventral anterior (VA) thalamic neurons to electrical stimulation of relay nuclei, ventrobasal complex (VB), lateral (GL) and medial (GM) geniculate bodies, were studied in cats immobilized with d-tubocurarine. 72.2% of R and 76.2% of VA investigated neurons responded to VB stimulation, while GM stimulation caused responses only in 15.0% of R and 27.1% of VA neurons and GL stimulation in 10.2% of R and 19.6% of VA neurons. The responses of R-VA neurons to relay nuclei stimulation were expressed, as a rule in excitation. Two types of excited neurons were distinguished: the first group responded to stimulation of afferent inputs by the discharge of 5-15 spikes at a frequency of 250-300 p/s, the second group responded by single action potential. According to peculiarities of their responses, the neurons of the first group are resembling inhibitory interneurons. 2.2% of R and 7.8% of VA neurons responded to relay nuclei stimulation by antidromic spikes. Among R and VA neurons there are cells which respond to stimulation of one, two and even three different relay nuclei. If stimulation of one relay nucleus is followed by a response of R or VA neuron, the preceding stimulation of another relay nucleus, with the time interval between the conditioning and testing stimuli being less than 30-50 ms, induced the inhibition of the response to the testing stimulus.