The mediodorsal nucleus is a large nucleus in the middle of the thalamus, near the midline on the inner side of the Y-shaped internal medullary lamina, one on each side. It relays input from the amygdala and the smell cortex to the prefrontal cortex. [1][2][3]
The 3D brain needs JavaScript. The text below still says where the mediodorsal nucleus is and what it does.
Opens cut by a front (coronal) slice through the thalamus, which holds the mediodorsal nucleus. 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 thalamus, on both sides. The mediodorsal nucleus is the middle, inner part of the thalamus; BodyParts3D has no shape for it (its only thalamic nuclei are the two geniculate bodies), so the whole thalamus is lit and nothing is drawn at a guessed point. [1][2]
Lit here: the thalamus, the part that holds the mediodorsal nucleus — see it on its own page.
Where it is
It lies at the midline side of the thalamus, medial to the internal medullary lamina, which separates it from the other thalamic nuclei. [2][1]
It belongs to the medial group, one of the three groups (anterior, medial, lateral) that the lamina divides each thalamus into; the medial group is split into the mediodorsal nucleus and the midline group. [3]
It has four parts: paralaminar, magnocellular, parvocellular and densocellular. [1]
What it does
It relays inputs from the amygdala and the olfactory cortex and projects to the prefrontal cortex and the limbic system. [1]
One classic definition of the prefrontal cortex is the cortex that receives projections from the mediodorsal nucleus. [4]
Smell is the one sense that does not stop in the thalamus before reaching the cortex, but a second route does go through it: the piriform cortex projects to the mediodorsal nucleus, which projects to the orbitofrontal cortex. [5][6]
Research in people now sees it less as a store for long-term memory and more as a regulator of cortical networks, linking what was just sensed to the action that comes next. [2]
Connections
Its outputs diverge to several prefrontal areas: different parts project to different frontal areas, and to the anterior cingulate cortex and the insula. [2]
It is thought to pass eye-movement signals from the superior colliculus to the frontal eye fields. [1]
Other names
Also called the medial dorsal, dorsomedial or mediodorsal nucleus of the thalamus, shortened to MD; it is not the dorsomedial nucleus of the hypothalamus. [1][2][7]
Size
The model has no shape for the mediodorsal nucleus itself, so it is not measured here. The left thalamus that holds it measures about 37 mm front to back, 24 mm top to bottom and 24 mm side to side on this model (the box it fits in, not its volume). [8]
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.