The dentate gyrus is one of the subfields of the hippocampus, in the hippocampal formation of the temporal lobe; one on each side. It is the first stage of the hippocampus’s trisynaptic circuit, taking its input from the entorhinal cortex. [1]
The 3D brain needs JavaScript. The text below still says where the dentate gyrus is and what it does.
Opens cut by a front (coronal) slice through the hippocampus, which holds the dentate gyrus. 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 hippocampus, on both sides. The dentate gyrus is a subfield inside the hippocampus; most of it is not on the brain’s surface. It has no shape of its own in the BodyParts3D model, so nothing is drawn at a guessed point. [1]
Lit here: the hippocampus, the part that holds the dentate gyrus — see it on its own page.
Where it is
The hippocampal formation is made of the hippocampus proper (fields CA1 to CA4), the dentate gyrus, the subiculum and the presubiculum. [1][2]
Most of it is hidden, but its front inner end, the tail of the dentate gyrus or band of Giacomini, shows on the underside of the uncus. [1]
It has three layers: an outer molecular layer, a middle layer of tightly packed granule cells and an inner polymorphic layer, the hilus (once named CA4). [1]
What it does
As part of the trisynaptic circuit it is thought to contribute to forming new episodic memories and to the spontaneous exploration of new places. [1]
A pre-processing step: it separates very similar inputs into distinct patterns (pattern separation), so a new memory is stored apart from similar ones; the next field, CA3, encodes, stores and retrieves. [1]
Its subgranular zone is one of the two main sites of adult neurogenesis, the making of new neurons in the adult brain, in many mammals; whether this happens to a significant degree in adult humans is still debated. [1]
Its granule cells form late: in rats about 85% are made after birth; in humans they begin at gestation weeks 10.5 to 11 and go on forming after birth. [1]
Connections
Input: the perforant path from the entorhinal cortex, whose layer II projects mainly to the dentate gyrus and field CA3; it receives no direct input from other parts of the cortex. [1][3]
Output: its granule cells send unmyelinated axons, the mossy fibres, through the hilus to the pyramidal cells of field CA3 and to the hilus’s own mossy cells. [1][4]
Other names
Named for its tooth-like projections; abbreviated DG, and its molecular and granule layers together are sometimes called the fascia dentata. [1]
Size
The model has no shape for the dentate gyrus itself, so it is not measured here. The left hippocampus that holds it measures about 43 mm front to back, 22 mm top to bottom and 20 mm side to side on this model (the box it fits in, not its volume). [5]
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.