dentate gyrus

Brain: Dentate gyrus
Diagram of hippocampal regions. DG: Dentate gyrus.
Coronal section of brain immediately in front of pons. (Label for "Gyrus dentatus" is at bottom left.)
Latin	gyrus dentatus
Gray's	subject #189 827
Part of	Temporal lobe
Artery	Posterior cerebral Anterior choroidal
NeuroNames	hier-161
MeSH	Dentate+Gyrus

The dentate gyrus is part of the hippocampal formation. It contains granule cells, which project to the pyramidal cells, but mostly to the interneurons of the CA3 subfield of the hippocampus. The granule cells are the principal excitatory neurons of the dentate gyrus. The major input to the dentate gyrus (the so-called perforant pathway) is from layer 2 of the entorhinal cortex, and the dentate gyrus receives no direct inputs from other cortical structures. The perforant pathway is divided into the medial perforant path and the lateral perforant path, generated, respectively, at the medial and lateral portions of the entorhinal cortex. The medial perforant path synapses onto the proximal dendritic area of the granule cells, while the lateral perforant path does so onto the distal dendrites of these same cells.

The dentate gyrus is also one of the few regions of the brain where neurogenesis takes place. Neurogenesis is thought to play a role in the formation of new memories. It has also been found to increase in response to both antidepressants and physical exercise. On the converse, however, endogenous and exogenous glucocorticoids such as cortisol inhibit neurogenesis. Both endogenous and exogenous glucocorticoids are known to cause psychosis and depression,^[1], implying that neurogenesis may improve symptoms of depression. In a 2007 study, investigators observed that electrical chatter in the dentate gyrus contracts in depressed rats but expands again after the animals receive antidepressants. The region may represent a common pathway or intersection for brain activity in those suffering from depression ^[2]

The dentate gyrus plays a role in recognizing the differences that make each place unique. Thus, damage to the dentate gyrus can play a role in déjà vu.[1]

External links

• Slide at psycheducation.org
• BrainMaps at UCDavis Dentate gyrus

• "Dentate Gyrus NMDA Receptors Mediate Rapid Pattern Separation in the Hippocampal Network". Science 7 June 2007 DOI: 10.1126/science.1140263 - The source of deja vu

References

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