<Li> affect decision - making and induce approach behavior (via the assignment of motivational salience to rewarding stimuli); </Li> <Li> elicit positive emotions, particularly pleasure . </Li> <P> The brain structures that compose the reward system are located primarily within the cortico - basal ganglia - thalamo - cortical loop; the basal ganglia portion of the loop drives activity within the reward system . Most of the pathways that connect structures within the reward system are glutamatergic interneurons, GABAergic medium spiny neurons, and dopaminergic projection neurons, although other types of projection neurons contribute (e.g., orexinergic projection neurons). The reward system includes the ventral tegmental area, ventral striatum (i.e., the nucleus accumbens and olfactory tubercle), dorsal striatum (i.e., the caudate nucleus and putamen), substantia nigra (i.e., the pars compacta and pars reticulata), prefrontal cortex, anterior cingulate cortex, insular cortex, hippocampus, hypothalamus (particularly, the orexinergic nucleus in the lateral hypothalamus), thalamus (multiple nuclei), subthalamic nucleus, globus pallidus (both external and internal), ventral pallidum, parabrachial nucleus, amygdala, and the remainder of the extended amygdala . The dorsal raphe nucleus and cerebellum appear to modulate some forms of reward - related cognition (i.e., associative learning, motivational salience, and positive emotions) and behaviors as well . </P> <P> Most of the dopamine pathways (i.e., neurons that use the neurotransmitter dopamine to communicate with other neurons) that project out of the ventral tegmental area are part of the reward system; in these pathways, dopamine acts on D1 - like receptors or D2 - like receptors to either stimulate (D1 - like) or inhibit (D2 - like) the production of cAMP . The GABAergic medium spiny neurons of the striatum are components of the reward system as well . The glutamatergic projection nuclei in the subthalamic nucleus, prefrontal cortex, hippocampus, thalamus, and amygdala connect to other parts of the reward system via glutamate pathways . 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 . </P>

Where is the pleasure/reward center located in our brain