Differential contributions of hippocampus, amygdala and perirhinal cortex to recognition of novel objects, contextual stimuli and stimulus relationships.
This study examined contributions of the hippocampus, amygdala and perirhinal cortex to memory. Rats performed a cover task, and changes to stimulus identity or relationships were used to test incidental memory. Rats with hippocampal damage showed deficient responses to relationship changes, but demonstrated knowledge of the position and identity of the target object. They over-focused on the most predictive stimuli, and failed to acquire associations including surrounding cues. Rats with amygdala damage responded to changes involving distal stimuli, and showed deficient responses to novel objects and object relationships. These rats may be highly reliant on relational representations, resulting in a reduced salience for individual novel stimuli. Rats with perirhinal damaged responded to novel stimulus relationships and distal cues, but showed deficient responses to novel objects, suggesting that changes in identity had reduced salience. Implications for declarative and conjunctive hippocampal theories are discussed.
Moses
Sandra N
SN
Rotman Research Institute, Baycrest Centre for Geriatric Care, 3560 Bathurst St., Toronto, Ont., Canada M6A 2E1. smoses@rotman-baycrest.on.ca
Cole
Carrie
C
Driscoll
Ira
I
Ryan
Jennifer D
JD
D000679:Amygdala / Q000502:physiology* / Q000503:physiopathology; D000818:Animals; D001925:Brain Damage, Chronic / Q000473:pathology / Q000503:physiopathology; D003463:Cues; D003714:Denervation; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology; D006624:Hippocampus / Q000502:physiology* / Q000503:physiopathology; D007859:Learning Disabilities / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008568:Memory / Q000502:physiology*; D008569:Memory Disorders / Q000473:pathology / Q000503:physiopathology; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology* / Q000503:physiopathology; D009483:Neuropsychological Tests; D020534:Parahippocampal Gyrus / Q000502:physiology* / Q000503:physiopathology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D051381:Rats; D020318:Rats, Long-Evans