Contribution of ventrolateral prefrontal cortex to the acquisition and extinction of conditioned fear in rats

The ventrolateral, agranular insular portion of prefrontal cortex (PFC) in rats is involved in visceral functions and has been shown to be involved in emotional processes. However, its contribution to aversive learning has no t been well defined. Classical fear conditioning has been a powerful tool f or illuminating some of the primary neural structures involved in aversive emotional learning. We measured both the? acquisition and the extinction of conditioned fear following lesions of the ventrolateral PFC of rats. Lesio ns reduced fear reactivity to contextual stimuli associated with conditioni ng without affecting CS acquisition, and had no effect an response extincti on. Ventrolateral PFC may normally be involved in the processing of context ual information while not being directly involved in extinction processes w ithin the aversive domain. (C) 1999 Academic Press.