 There are several explanations as to why the mesolimbic dopamine pathway is central to circuits mediating reward.First, there is a marked increase in dopamine release from the mesolimbic pathway when animals engage in intracranial self-stimulation.Second, experiments consistently indicate that brain-stimulation reward stimulates the reinforcement of pathways that are normally activated by natural rewards, and drug reward or intracranial self-stimulation can exert more powerful activation of central reward mechanisms because they activate the reward center directly rather than through the peripheral nerves.