[Neuronal activity of the caudate nucleus in the cat upon presentation of positive and negative conditioned stimuli].

Spike activity in the cat caudate nucleus was studied during accomplishment of a positive instrumental defensive reflex, as well as during formation of inhibitory--differentiation and extinction--conditioned reflexes. Most of the neurones which exhibited plastic reorganizations, were localized in the dorsal segment of the caudate nucleus. With a well stabilized conditioned reflex, spike reactions of the inhibitory sign prevailed. In response to inhibitory stimuli, bioelectrical activity set in neurones, whose spike discharges were suppressed during realization of the conditioned reflex, as well as a change of the sign of evoked spike reactions in some cells reacting to the positive stimulus.