Lateral Habenula and Aversive Motivational Value. The lateral habenula (LHb) receives excitatory afferent projections from the globus pallidus internal segment (GPi). The GPi is located more lateral but is placed in the same slice for illustration purposes. The LHb sends efferent projections to target the substantia nigra, ventral tegmental area, dorsal and medial raphé nuclei, and locus coeruleus, brainstem nuclei with high concentrations of dopamine, serotonin, and norepinephrine. These modulatory signals are mediated by the rostromedial tegmental nucleus (not pictured). Serotonin neurons send inhibitory projections to the GPi that suppress the excitatory projections from GPi to the LHb.