Which brain region is the primary source of serotonin?

Which brain region is the primary source of serotonin?

• A. Locus coeruleus
• B. Raphe nuclei
• C. Substantia nigra
• D. Amygdala

Answer: (B)

Serotonin comes from neurons in the raphe nuclei along the brainstem, especially the dorsal and median raphe. These midline nuclei send widespread projections throughout the brain, influencing mood, sleep, appetite, and pain. The locus coeruleus is the main source of norepinephrine, the substantia nigra contains dopaminergic neurons important for movement and reward, and the amygdala is a key limbic structure for emotion processing—not the primary source of serotonin. So, the raphe nuclei are the main origin of serotonergic neurons.

Serotonin comes from neurons in the raphe nuclei along the brainstem, especially the dorsal and median raphe. These midline nuclei send widespread projections throughout the brain, influencing mood, sleep, appetite, and pain. The locus coeruleus is the main source of norepinephrine, the substantia nigra contains dopaminergic neurons important for movement and reward, and the amygdala is a key limbic structure for emotion processing—not the primary source of serotonin. So, the raphe nuclei are the main origin of serotonergic neurons.