Modification of the Autonomic Component of the Conditioned Emotional Response

Abstract

A series of experiments was conducted to clarify the role of the autonomic nervous system in the acquisition and maintenance of the conditioned emotional response (CER). In Exp. 1 the reactivity of either the sympathetic or the parasympathetic system was altered by drugs during maintenance testing of the CER. 12 rats were trained to bar-press for sugar water on a VI 30-sec. schedule; 6 CER trials were administered during each 2-hr. session. The intensity of the unconditioned stimulus (electric shock) was adjusted for each S so as to suppress responding during the CER signal (tone) to approximately 50% of normal pressing rate. Neither the sympathetic agents (adrenalin, Chlorpromazine, Dibenzyline), nor the parasympathetic agents (methacholine chloride, propantheline, atropine sulfate) reliably altered bar-press rates during the CER trials. Exp. 2 demonstrated that the autonomic agents, in the dosages used, were in fact altering autonomic reactivity as indexed by heart-rate measures. In Exp. 3 acquisition of the CER by 18 rats was found not to be affected by autonomic alteration as produced by drugs.