ABSTRACT
This chapter aims to determine whether curarized rats can learn a different type of autonomically controlled visceral response, namely, the contraction or relaxation of the large intestine. It provides information on experiments that determine whether or not intestinal contractions could be modified by instrumental training and determine the specificity of visceral learning. The hypothesis that both the intestinal and cardiac responses were mediated by the learning of some general reaction, such as arousal, struggling, or a shift in the sympathetic-parasympathetic balance, would predict exactly the opposite results. When deeply curarized rats, maintained on artificial respiration, were rewarded by electrical stimulation of the medial forebrain bundle for relaxation of the large intestine, spontaneous intestinal contraction decreased; but if subsequently rewarded for intestinal contraction, it increased to above base-line level. Intestinal contraction increased when rewarded, decreased when relaxation was rewarded, and remained virtually unchanged when either increased or decreased heart rate was rewarded.
