NORADRENALINE AND EXTINCTION OF CONDITIONED TASTE-AVERSION IN THE RAT

Depletion of forebrain noradrenaline to less than 5% of control values using the selective neurotoxin 6-hydroxydopamine failed to affect the acquisition learning of a lithium chloride-induced taste aversion to saccharin solution. Extinction of this aversion, as measured by subsequent saccharin exposures in the absence of lithium chloride poisoning, was retarded in the lesioned animals. Control groups indicated that this was a real taste aversion and not due to either nonspecific illness or enhanced neophobia. It is concluded that the resistance to extinction seen in extinction of instrumental learning situations also applies to those processes operative in taste aversion extinction. © 1979 Academic Press, Inc.