[Participation of the neostriatum in mechanisms of instrumental behavior].

The paper is devoted to the study of the neostriatum role in the mechanism of instrumental learning. In the experiments on cats with damaged dorsal segment of the caudate nucleus head, deficit of forming new instrumental reflexes and achieving complex tasks was revealed. Damage of the caudate neucleus had a most pronounced negative influence on the process of differentiation elaboration. High- and low-frequency stimulation of this structure in dogs did not disturb solution of an instrumental task: the end result was achieved, but the characteristics of many parameters of the motor act--latency, amplitude, duration--were significantly changed. The presented facts suggest that the basal ganglia play functionally different roles in the period of formation of instrumental conditioned reflexes and in the period of realization of consolidated connections. Possible mechanisms of neostriatum participation in the processes of elaboration and realization of instrumental reflexes of various motivational value are discussed.