[The effect of electrostimulation of the caudate nucleus and somatosensory cortex on defensive instrumental reactions in dogs].

It has been shown that the effect of stimulation of the caudate nucleus head in the contralateral hemisphere differs at different stages of achievement of a defensive instrumental habit in dogs. Stimulation preceding the action of the conditioned signal or delivered simultaneously with the beginning of the latter did not change the criteria for the achievement of successive programs of the instrumental defensive reaction. Stimulation of the same areas in the last phase of the instrumental response, as a rule, lead to the cessation of instrumental movement. A conclusion has been drawn that in a defensive situation the inhibitory influence of the caudate nucleus on instrumental behaviour of intact dogs is not so sharply expressed as in experiments with alimentary reinforcement. In dogs with a preliminary ablation of the CI and CII cortical zones of the contralateral hemisphere, stimulation of the caudate nucleus head was attended with a sharp drop in every criterion of the instrumental defensive reactions.