Combined hippocampal and amygdala lesions block learning of a response-independent form of occasion setting.
This study compared rats with dorsal striatal, ventrolateral prefrontal cortical, and combined lesions of the hippocampus and amygdala to sham controls on a conditional discrimination task in which contextual cues modulated a taste aversion. All groups were able to acquire this occasion setting task. The 2nd experiment functionally minimized the stimulus-response component of the paradigm, creating a "tasteless" form of occasion setting. Rats with pretraining lesions of the hippocampus and amygdala were impaired compared with shams on the acquisition of this tasteless occasion setting task. Rats with posttraining combined lesions did not retain the ability to perform the tasteless occasion setting task learned preoperatively. Rats with selective lesions of either the hippocampus or the amygdala alone were not impaired in the acquisition of the tasteless occasion setting task. The findings suggest that this occasion setting task may be learned by several redundant neural systems.
Clarke
H A
HA
Department of Anatomy and Cell Biology, University of Toronto, Ontario, Canada.
Skinner
D M
DM
van der Kooy
D
D
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001245:Association Learning / Q000502:physiology*; D001362:Avoidance Learning / Q000502:physiology*; D001931:Brain Mapping; D003214:Conditioning, Classical / Q000502:physiology*; D003342:Corpus Striatum / Q000502:physiology; D004924:Escape Reaction / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D011939:Mental Recall / Q000502:physiology; D009415:Nerve Net / Q000502:physiology; D009949:Orientation / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013649:Taste / Q000502:physiology*