Interneuron relationships in the basolateral amygdala in cats treated to select food on the basis of quality

Cats were initially trained to make operant conditioned food responses to light by an "active selection of reinforcement" method. Provision of low-quality (a mixture of meat and bread) or high-quality (meat) reinforcement depended on the animal pressing a pedal in response to switching on a light with a short (1 sec) or long (10 sec) delay. Some animals responded to long delays--group I, animals with "self control," while others responded with short delays--group II, "impulsive" animals. Implanted semimicroelectrodes were used in chronic experiments to record multineuron activity in the basolateral amygdala. Cross-correlation analysis was used to study interneuron interactions in the spike discharges of individual neurons, extracted from multineuron activity. The numbers of interneuron interactions were significantly higher in "impulsive" cats of group II in all behavioral situations than in animals with "self control," and were dominated in "impulsive" animals by the shortest connections, with latencies of 0-30 msec. The largest numbers of connections in both groups were seen on omission of the conditioned pedal-pressing movement response, i.e., when the reinforcement selection task was more difficult. These data indicate that the basolateral amygdala should be regarded as a structure determining the individual typological characteristics of the animals' behavior.