Lesions of Orbitofrontal Cortex Impair Rats' Differential Outcome Expectancy Learning but Not Conditioned Stimulus-potentiated Feeding

Patients with damage to the orbitofrontal cortex (OFC) display various impairments in cognitive and affective function, including a reduced ability to use information about the consequences of their actions to guide their behavior. In this study, rats with neurotoxic lesions of the OFC failed to use specific expectancies about outcomes to guide their learning of an instrumental discrimination task. In contrast, lesioned rats were unimpaired in a measure of learned motivational function, the potentiation of feeding under conditions of food satiation, by a conditioned stimulus that had been paired with food while the rats were food deprived. Notably, performance of both of these tasks has been shown to depend on the function of the basolateral amygdala (BLA), a region that is richly interconnected with the OFC. Thus, the present results are consistent with the view that the acquisition and use of specific outcome expectancies to guide behavior critically involve a neural system that includes the BLA and the OFC, but they indicate that certain motivational properties acquired by cues on the basis of appetitive learning involve BLA circuitry apart from the OFC.