any of various areas of the brain (including areas of the hypothalamus and limbic system) that, upon intracranial self-stimulation (see intracranial stimulation), have been implicated in producing pleasure. The existence of pure pleasure centers has not been definitively established, particularly because the self-stimulation response rate varies according to such factors as the duration and strength of the electrical stimulation. Also called reward center. [proposed by James Olds]