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pubmed:abstractText |
In this study, the authors tested the hypothesis that the basolateral amygdala (BLA), orbitofrontal cortex (OFC), nucleus accumbens core (NA-core), and the extended hippocampus mediate different aspects of the development-maintenance of unique reward expectancies produced by the differential outcomes procedure (DOP). Rats were trained with either DOP or a nondifferential outcomes procedure (NOP) on a simple discrimination task. Fornix lesions did not affect either version of the task, demonstrating that the extended hippocampal system has no role in stimulus-outcome (S-O) associations. In contrast, in the DOP condition, BLA lesions impaired performance throughout training, OFC lesions impaired choice accuracy only in the later maintenance phase, and NA-core lesions resulted in enhanced learning. These results suggest that BLA and OFC are important for establishment (BLA) and behavioral maintenance (OFC) of S-O associations, whereas the NA-core is not needed and can in fact impede using multiple S-O associations. No impairments were observed in the NOP condition, demonstrating that these structures are not critical to stimulus-response learning.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, N.I.H., Extramural
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