Influence of the midbrain reticular formation upon reactions of cortical neurons in rabbits during learning.

Abstract

1. The effect of low-frequency stimulation of the RF of the midbrain upon the reaction of the neurons of the visual region of the cortex during elaboration of a conditioned defensive reflex to light flashes was investigated in experiments on waking, unimmobilized rabbits. 2. The linking of a reinforcing stimulus (in this case ECS) to the light flashes resulted in a strengthening of the first phase of activaion, a shortening of the inhibitory pause, an appearance of additional burst activity, and a weakening of the initial postinhibitory activation. This effect of the reinforcement was imitated during responses to light flashes (the conditioned stimulus). 3. Stimulation of the RF generally strengthened the action of ECS to light flashes which had become a signal for the defensive reflex. 4. A reorganization of the structures of the phase reactions to light flashes toward the side of an increase in the number of phases of activation and inhibition was observed in a number of neurons against a background of low-frequency stimulation.