[Neuronal organization of a focus of unconditioned excitation in the cat sensomotor cortex]

The impulse activity of sensorimotor area neurones, situated near the point of its direct electrical stimulation used as a reinforcing stimulus, was studied in cats. The rearrangement of impulse activity during reflex elaboration consisted in the reduction of frequency of background activity, in changes in the character of neuronal reactivity and of the pattern of response to the signal and reinforcing stimuli. During the reflex elaboration the percentage of polymodal neurones increased. Tonic response to the conditioned sound stimulus changed into a phasic one. The inhibitory component of responses to direct electrical stimulation of the sensorimotor cortex became more protracted.