Microinjections of serotonin and glutamic acid into the globus pallidus in conditions of free selection between a light and a dark chamber showed these substances to have antiaversive activity in rats in the "threatening situation" test but not in the "illuminated area" test. Local administration of dopamine and GABA into this basal ganglia formation had no effect on the mechanisms of voluntary movement but countered anxiety states in both behavioral models. These results provide evidence that the neurotransmitter systems of the dorsal pallidum have different degrees of involvement in the operative control of behavior when the modality of the aversive stimulus changes.