Antipsychotic drugs (neuroleptics) used to treat human psychiatric patients have long been known to suppress rewarded behaviours in laboratory animals. Controversy exists, however, over whether these behavioural disruptions result from reductions in pleasure/reward ("limbic system" effects), or from an interruption of the brain's control of movement ("extrapyramidal" effects). In previous work, Dr. Ettenberg has developed laboratory tests which clearly distinguish between the reward-attenuating and performance- debilitating actions of these drugs. His results suggest that neuroleptics can attenuate the rewarding properties of a number of positive reinforcers, such as the taste of sugar. Dr. Ettenberg will conduct experiments to extend these results, testing the generality with which neuroleptics attenuate the rewarding effects of several different positive reinforcing rewards, and also, to identify those critical brain regions responsible for the drugs' actions. This work will provide scientifically relevant information about the mood-altering or pleasure-diminishing consequences of antipsychotic drugs, and also help in the identification of brain mechanisms responsible for positive affective states.
