Serotonin neurons (5-HT) in the brain
The source nuclei for the serotonin neurons are located in the Raphe nuclei in the pons and medulla. These project throughout the brain, brain stem and spinal cord. The serotonergic pathways spread extensively throughout the brainstem, the cerebral cortex and the spinal cord.
In addition to mood control, serotonin has been linked with a wide variety of functions, including the regulation of sleep, pain perception, body temperature, blood pressure and hormonal activity.
Outside the brain, serotonin is involved in regulation of the gastrointestinal and cardiovascular system.