[Reactions of neurons in the reticular and ventral anterior thalamic nuclei to stimulation of the ventrolateral nucleus of the thalamus and motor cortex].

Responses of 137 neurons located in oral parts of reticular (R) and ventral anterior (VA) thalamic nuclei to electrical stimulation of the ventrolateral nucleus (VL) and motor cortex (MI) were studied in 17 cats immobilized with d-tubocurarine. 10.5% of the investigated neurons responded to VL stimulation by antidromic spike (latency 0.7--3.0 ms). 11.0% of the neurons responded antidromically to MI stimulation (latency 0.4--4.0 ms). Neurons with axon sending one branch to VL and the other to MI were found. 78.9% of the neurons responded to VL stimulation with orthodromic excitation (after stimulation of MI this type of response was found only in 52.5% of neurons). 55.6% of R and VA neurons responded to VL stimulation by discharges composed of 3--20 spikes with frequency of 130--530/per second. After MI stimulation discharges of the same type were observed only in 30.5% of the investigated neurons. Inhibition was found in 6.8% of the studied neurons. 55.7% of R and VA neurons demonstrated the convergence of the effects from VL and MI. Corticofugal influences from MI on responses of R and VA neurons to the VL testing stimuli could be inhibitory as well as excitatory.