[Local disinhibition with bicuculline does not break the trained relationship between afferent input and efferent output in cat motor cortex].

Neurons of the cat motor cortex related to the lifting-withdrawal phase of forepaw placing reaction are preferentially activated by tactile stimulation of the dorsal surface of the forepaw. The placing reaction was altered in such a way that the innate "dorsal placing" was subjected to extinction and was substituted for the newly acquired conditioned reaction in response to the ventral side stimulation. This alteration of placing reaction led to the inversion of the innate input-output relationship in the motor cortex. The neurons related to forepaw lifting-withdrawal began to be activated by tactile stimulation of the ventral rather than dorsal forepaw surface. Local cortical disinhibition by bicuculline application at the recording site qualitatively changed neither normal input-output relationships nor inverse relationships after placing reaction alteration. This suggests that alteration of the sensorimotor coordination in cat motor cortex is underlain by changes in excitatory rather than inhibitory connections.