Dorsal Raphe Nuclei (DRN)

A heterogeneous brainstem nucleus located in the midbrain and pons. Neurons in the dorsal raphe nucleus (DRN) utilize many transmitters to control various physiological functions, including learning, memory, and affect. The DRN’s most abundant transmitter is serotonin – it is the largest serotonergic nucleus in the human brain. The DRN is strongly associated with brain dysfunction, especially mood disorders such as depression and Alzheimer’s disease.

Reference:

Michelsen, K. A., Prickaerts, J., & Steinbusch, H. W. (2008). The dorsal raphe nucleus and serotonin: Implications for neuroplasticity linked to major depression and Alzheimer's disease. Progress in brain research, 172, 233-264. https://doi.org/10.1016/s0079-6123(08)00912-6