Effects of electrical stimulation of the reticular formation and chlorpromazine on performance of trace conditioned avoidance response in the rat

The effects of electrical stimulation to the mesencephalic reticular formation and chlorpromazine on the performance of a trace conditioned avoidance response by rats were studied. Either treatment alone impaired the performance; this impairment was a function of level of stimulation or dose of the drug, respectively. The performance deficit was not present when a high intensity of stimulation of the reticular formation was combined with a moderate dose of chlorpromazine. However, the combination of a high dose of the drug with a low stimulation intensity interfered with the avoidance responding more than any other condition tested. These effects appeared to be independent of neutral or negative reinforcement effects of the stimulation, as tested in an independent situation.