POST-REINFORCEMENT EEG SYNCHRONIZATION DURING ALIMENTARY BEHAVIOR.

Abstract 1. 1. Cats were trained to manipulate a lever which delivered small amounts of liquid food (milk-broth) from a dispenser. Discrete periods of EEG synchronization were observed coincident to the development of this simple instrumental response. 2. 2. Slow wave synchronous activity in the EEG replaced low voltage fast activity when the animals received positive reinforcement. These “spindles” did not appear if the animals were not reinforced. They could be abolished by thalamic electrical stimulation at arousal parameters or by novel auditory stimuli, even though these internal and external stimuli were not intense enough to alter the behaving pattern of the cats in the instrumental situation. 3. 3. Water substituted for the milk-broth reward in a food deprived animal resulted in a disappearance of the post-reinforcement cortical synchronization. 4. 4. The EEG synchronization previously described during prolonged alimentary behavior was also observed in our animals under these circumstances. 5. 5. The presentation of a sensory stimulus in association with the delivery of larger amounts of food resulted in the classical conditioning of this synchronization. Extinction of the conditioned synchronization was also achieved. The prolonged presentation of a non-reinforced CS resulted in the reappearance of a synchronization, which, in this case, was associated with the extinction of an alimentary response.