 The medial forebrain bundle, which is a set of many neural pathways that mediate brain stimulation reward (i.e., reward derived from direct electrochemical stimulation of the lateral hypothalamus), is also a component of the reward system.Two theories exist with regard to the activity of the nucleus accumbens and the generation liking and wanting.The inhibition (or hyper­polar­ization) hypothesis proposes that the nucleus accumbens exerts tonic inhibitory effects on downstream structures such as the ventral pallidum, hypothalamus or ventral tegmental area, and that in inhibiting in the nucleus accumbens (NAcc), these structures are excited, "releasing" reward related behavior.