REGIONAL SPECIFICITY OF THE EMOTIONAL-AVERSIVE RESPONSE INDUCED BY CARBACHOL IN THE CAT BRAIN - A QUANTITATIVE MAPPING STUDY

In this paper, the emotional-aversive response induced by intracerebra l injection of carbachol has been studied in cats by recording their v ocalization as an index of emotional behavior. The carbachol-induced r esponses were quantitatively mapped in the basal forebrain and diencep halic regions using the cumulative time of the animal's vocalization a s a measure of response. The areas inducing the emotional- aversive re sponse extended along two axes: 1. longitudinally along the neuraxis, from the reticular formation through the hypothalamus to the rostro-ba sal forebrain; and 2. vertically along the fornix, from the mediobasal hypothalamus to the septal area. The highest magnitude of the respons e (vocalization time) was obtained from a strip of tissue extending fr om the septum and preoptic area to the dorsal perifornical area, the d orsomedial hypothalamic nucleus, the paraventricular nucleus and the p eriventricular stratum. The pattern of distribution of reactive and no nreactive sites showed anatomic specificity, with the highest sensitiv ity found within the close periventricular tissue of the third ventric le. It is suggested that carbachol mapping selectively delineates the muscarinic cholinoceptive portion of the aversive, emotional brain sys tem.