The raphe nuclei are a chain of cell groups along the midline of the brainstem, running through the midbrain, the pons and the medulla oblongata. They hold most of the brain’s serotonin neurons. [1][2]
The 3D brain needs JavaScript. The text below still says where the raphe nuclei are and what they do.
The midbrain, pons and medulla oblongata are lit together; the raphe nuclei are not drawn on their own. The side (sagittal) slice button cuts through them. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Not a separate shape in this atlas; lit: the part that holds it. Lit: the whole midbrain, pons and medulla oblongata. The raphe nuclei are cell groups on the midline inside the midbrain, pons and medulla oblongata; they have no shape of their own in the BodyParts3D model, so the three parts that hold them are lit and nothing is drawn at a guessed point. [1][3]
Lit here: the midbrain and the pons and the medulla oblongata, the parts that hold the raphe nuclei — see each on its own page.
They form a ridge of cells in the centre, the most medial part, of the brainstem; “raphe” is Greek for seam. [1]
By part: in the medulla oblongata the nucleus raphe obscurus, raphe pallidus and raphe magnus; in the pons the nucleus raphe pontis and the nucleus centralis inferior; in the midbrain the median raphe nucleus (nucleus centralis superior) and the dorsal raphe nucleus. [1]
What it does
They are the main source of serotonin in the brain: most of the brain’s serotonin neurons sit in them. [2][1]
The lower (caudal) group, the raphe magnus, pallidus and obscurus, projects down to the brainstem and spinal cord; the upper (rostral) group, the raphe pontis, median and dorsal raphe, projects up to the forebrain. [1]
Sleep and wake: serotonin from them mainly promotes wakefulness and holds back rapid eye movement (REM) sleep. [1]
Pain modulation: their descending fibres reach the spinal cord, where they help control the release of enkephalins that damp pain signals; the periaqueductal grey drives this route through the raphe magnus. [1][4]
Connections
They receive input from the periaqueductal grey of the midbrain, and project to the locus coeruleus among many other targets. [4][5]
Other names
Also written raphé nuclei; the individual groups have their own names (dorsal raphe, median raphe, raphe magnus, pallidus, obscurus, pontis). [1]
Size
The model has no shape for the raphe nuclei itself, so it is not measured here. The midbrain that holds it measures about 29 mm front to back, 17 mm top to bottom and 29 mm side to side on this model (the box it fits in, not its volume). [6]
The model has no shape for the raphe nuclei itself, so it is not measured here. The pons that holds it measures about 34 mm front to back, 29 mm top to bottom and 42 mm side to side on this model (the box it fits in, not its volume). [6]
The model has no shape for the raphe nuclei itself, so it is not measured here. The medulla oblongata that holds it measures about 33 mm front to back, 41 mm top to bottom and 27 mm side to side on this model (the box it fits in, not its volume). [6]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.