title: Differential involvement of the basolateral amygdala, orbitofrontal cortex, and nucleus accumbens core in the acquisition and use of reward expectancies.
abstract: 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.
authors: Department of Psychology, State University of New York at Binghamton, Binghamton, NY, USA. ramirezd@email.unc.edu
authors: Donna R
authors: DR
authors: Ramirez
authors: Lisa M
authors: LM
authors: Savage
mesh_terms: D000679:Amygdala / Q000502:physiology*; D000818:Animals; D004193:Discrimination Learning / Q000502:physiology; D005508:Food Deprivation; D020712:Fornix, Brain / Q000033:anatomy & histology / Q000502:physiology; D008297:Male; D009714:Nucleus Accumbens / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward