The priming effect of rewarding brain stimulation persists following blockade of D2-like dopamine receptors

Receipt of an intense reward boosts motivation to work for more of that reward. This phenomenon is called the priming effect of rewards. A previous study demonstrated that the priming effect of rewarding medial forebrain bundle stimulation was remarkably resilient following administration of medium-high doses of pimozide. Here, we used the operant-chamber paradigm described in the preceding paper to assess the dependence of the priming effect on D2-like dopamine receptors. We found that the priming effect also proved resilient to the effect of eticlopride, a selective D2-like receptor antagonist. The results are discussed within the framework of a new model of brain reward circuitry in which non-dopaminergic medial forebrain bundle fibers and dopamine axons provide parallel inputs to the final common paths for reward and incentive motivation.