Pharmacological patterns in subcortical reinforcement behavior

Abstract

By means of intercurrent hypothalamic positive reinforcement and tegmental negative reinforcement tests, drug actions on two different brain-stimulated behaviors were assessed simultaneously. Chlorpromazine at 2 mg/kg was effective in antagonizing both hypothalamic positive reinforcement behavior; however, it did produce sustained reduction of tegmental negative but it regularly caused a greater percentage deficit in hypothalamic positive behavior. Meprobamate at 100 mg/kg did not regularly produce lasting reduction of hypothalamic positive reinforcement behavior; however, it did produce sustained reduction of tegmental negative reinforcement behavior. In the case of meprobamate, therefore, there was regularly a greater percentage deficit in tegmental negative behavior. While the imbalanced action of chlorpromazine against positive reinforcement may be explained by aspects of the testing procedure (such as the widely different speeds of the two behaviors) and have no relation to the difference in emotional sign, the opposite imbalanced action of meprobamate makes it quite clear that the two chemicals have quite different modes of action in relation to these brain and behavior tests. The findings with LSD and amphetamine were less informative; LSD had regularly a brief suppressing effect on hypothalamic behavior; amphetamine augmented the slow tegmental negative behavior but often slowed the rapid hypothalamic positive behavior.