Experimental investigation of the role of hypothalamic and associated "limbic system" structures in the organization of appetitively or aversively motivated behaviors (e.g., feeding, drinking, aggressive behaviors, or escape-avoidance). Techniques include: (a) the direct application of drugs to subcortical tissue; (b) the transections of fibers of passage by microsurgical procedures; (c) electrolytic lesions. The dependent variables include instrumental behaviors such as lever pressing, opening doors, etc., as well as "unlearned" behaviors such as feeding, drinking, fighting, etc. Attempts are made to correlate the behavioral data with changes in brain amines (n-epinephrine, dopamine, serotonin).