[Generation and propagation of direct responses of intact and chronically isolated strips of cortex].

Generation and transmission mechanisms of direct cortical responses were studied in the acute experiment on unanesthetized curarized cats ant intact cortex or a chronically isolated cortical strip. All studied properties of the direct response at the intact cortex and isolated strip of gyrus suprasilvius are identical. The blockage of cortical muscarinic cholinoreceptors between the stimulating and recording electrodes prevents or significantly decreases excitation transmission throught his part of the cortex. This can be explained by a polysynaptic mechanism of the response transmission. Neuronal nets providing the propagation of direct responses are anisotropic. Both normal and inverted (by GABA, nembutal or coagulation of the cortical surface) direct responses are increased aiter anticholinesterase drug (galanthamine) application. Amizil abolishes all these potential. A suggestion is made that both deep and superficial components of the direct cortical response are generated by endogenous cortical cholinergic elements.