Monoaminergic control by amygdalar nuclei of the reinforcing action of conditional stimuli.

The influence of microinfusion of 5-HT, NE, and DA into the amygdalar nuclei on the accomplishment of conditioned reinforcing and conditioned trigger reflexes which are constituents of the CADR was studied in cats with a developed conditioned alimentary discrimination reflex (CADR) in response to two conditional light stimuli set apart on different sides of a box. It was established that 5-HT in doses of 30-50 micrograms in a volume of 5 microliters elicits inhibition; the same doses of NE, by contrast, induces the "hanging-up" of the animals on conditional and conditional--unconditional stimuli which possess the property of reinforcement during the execution of the CADR. The microinfusion of DA in doses of 30-60 micrograms recalls, from animal to animal, the action of 5-HT and NE. It is hypothesized that the inhibitory functions of 5-HT and the activating actions of NE in the amygdalar nuclei support this structure's control of reinforcing conditional and conditional--unconditional reflexes and the perception of the reinforcing action of conditional stimuli. It is hypothesized that the DAergic innervation of the amygdala does not participate directly in conditioned reflex activity.