James olds and peter milner located reward centers in the brain structure known as the nucleus accumbens. The nucleus accumbens is the main component of the ventral striatum located in the basal forebrain rostral to the preoptic part of the hypothalamus. The main role of the nucleus accumbens is in mediating reward. The nucleus accumbens functions by reinforcing stimuli such as when eating food, processing rewarding stimuli, and by both rewarding and reinforcing such as when having exercise, sex and taking drugs. The nucleus accumbens is a crucial component of a major dopaminergic pathway in the brain which is stimulated during rewarding experiences.