Function of the nucleus accumbens within the context of the larger striatal system

There is accumulating evidence that the nucleus accumbens plays an important role in spatial navigation, and it has been suggested that the accumbens functions to integrate spatial and reward information to affect behavioral performance (e.g., Lavoie & Mizumori, 1994). Here, a hypothesis is proposed that more specifically takes into consideration the nature of the contribution of the accumbens. Specifically, it is argued that the accumbens operates in conjunction with the caudate-putamen to provide organisms with a response reference system whereby the success of current behavioral strategies can be evaluated. The accumbens is postulated to carry out this function with respect to current changes in the sensory (spatial) environment, whereas the caudate-putamen evaluates the effectiveness of current responses, relative to response efficacy predicted by past experience. The striatum as a whole, then, endows the navigation system with a response-based mechanism by which memory representations and current environmental information (from the neocortex) can guide future spatial behaviors.