CONTRASTING EFFECTS OF CENTRAL NUCLEUS OF THE AMYGDALA AND DORSAL STRIATUM LESIONS ON ACTIVE-AVOIDANCE LEARNING AND ITS CONTEXTUAL MODIFICATION

We examined the effects of a contextual modification after acquisition of a two-way signalled active avoidance task in central nucleus of th e amygdala (CNA) and dorsal striatum (DS) lesioned rats. Results showe d that CNA lesioned rats learned to avoid shocks when the tone was pre sented, as rapidly as sham-operated animals showing that they were abl e to learn normally the different associations between the stimuli. In contrast, DS lesioned rats were retarded in learning the avoidance re sponse. A contextual modification leaded to a transient disruption of performances in sham-operated rats and to a long-lasting impairment in CNA rats, while DS rats were unaffected. This post-acquisition contex tual change provided further information about the way CNA and DS rats had learned the task. (C) 1997 John Wiley & Sons, Ltd.