[Evoked potentials in the dog sensomotor cortex during an avoidance reaction].

Elaboration of avoidance reaction (conditioned reflex of the second order), based on a preliminarily elaborated escape (conditioned reflex of the first order) from pulse electro-cutaneus stimulation of the paw, led to a well-defined reorganization of the activity of the cortical limb projection structures. By excitability parameters (EP and motor reaction thresholds) and by changes of parameters of EP to electro-cutaneous stimulation, in escape reactions the sensory functions are drastically enhanced. Judging from the EP pattern, in response to the first pulses of the series (intensification of late components, appearance of an additional late negative wave), these pulses act as signals. With the introduction of distant stimuli (clicks), the electric current loses its signal significance, and the EP produced by it are sharply depressed and simplified. In the somatosensory projection of the paw, EP to clicks observed before conditioning, decrease or disappear completely. But they appear in the motor projection of the paw. In conjunction with excitation parameters, these data suggest the predominance of efferent functions of the paw in avoidance reactions.