[Conditioned reflex switching-over in the rat after temporary functional decortication]

Conditioned switching-over was elaborated in white rats: in one situation an alimentary instrumental reflex to sound was elaborated, in another one--an electro-defensive avoidance reflex to the same sound, different time of the day and different chamber illumination used as the switching-over factor. One-time influence of spreading depression by means of bilateral application of 10% KCl solution for 1.5 min to dura mater brought to the disturbance of the conditioned switching-over for 2-3 days. Electrolytic destruction of posterior hypothalamus area was produced in some animals. After restoration of functions one-time application of spreading depression elicited deep and long-term disturbance of conditioned switching-over. Apparently more complex conditioned activity suffers greater at short-term elimination of cerebral cortex functions, especially in conditions of compensatory recovery after lesions of the central nervous system.