Approach responses for mesencephalic central gray stimulation are facilitated by D-amphetamine or food deprivation.

The effects of either injection of D-amphetamine or food deprivation on approach and escape responses produced by continuous electrical stimulation of either the lateral hypothalamus (LH) or the dorsal part of the mesencephalic central gray area (CG), were studied in the DBA/2 strain of mice using the shuttle-box technique. Both D-amphetamine and food deprivation decreased approach latency for LH as well as for CG stimulation. Changes in escape latency were observed only for LH stimulation and only during the food deprivation test. These results suggest the involvement of positive reinforcement circuits along with dorsal CG activation.