The<unk>  (Latin for 'the bit in a fold or seam') is a moderate-size cluster of nuclei found in the brain stem, and releases serotonin to the rest of the brain. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act in these nuclei, as well as at their targets .
Raphe nuclei
Gracile nucleus
Juxtarestiform body
Zona reticularis
Cuneate nucleus
Cochlear nuclei
Caudate nucleus
Vallecula of cerebellum