CURRENT CONTRAST DURING HYPOTHALAMIC SELF-STIMULATION

Hypothalamic self-stimulation rates of six rats were measured under varying combinations of the current intensities of the reinforcing and continuous background stimuli at the same hypothalamic locus. Response rate increased with intensity of reinforcement, up to a point and then remained constant. Reductions in response rate were associated with increasing background current. A second experiment demonstrated that locomotor behavior increased with increasing background current during self-stimulation sessions. Results suggest that background stimulation elicited responses Which were incompatible with operan t responding. © 1969, Psychonomic Journals, Inc.. All rights reserved.