Dentate gyrus

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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
NeuroNames	hier-161
MeSH	A08.186.211.577.405.200

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. Conversely, 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.

[edit] External links

• Slide
• BrainMaps at UCDavis Dentate gyrus

[edit] Notes and references

1. Jacobs BL, van Praag H, Gage FH. Adult Brain Neurogenesis and Psychiatry: A Novel Theory of Depression. Molecular Psychiatry. 2000;5:262-269.

Telencephalon (cerebrum, cerebral cortex, cerebral hemispheres) - edit

primary sulci/fissures: medial longitudinal, lateral, central, parietoöccipital, calcarine, cingulate frontal lobe: precentral gyrus (primary motor cortex, 4), precentral sulcus, superior frontal gyrus (6, 8), middle frontal gyrus (46), inferior frontal gyrus (Broca's area, 44-pars opercularis, 45-pars triangularis), prefrontal cortex (orbitofrontal cortex, 9, 10, 11, 12, 47) parietal lobe: postcentral sulcus, postcentral gyrus (1, 2, 3, 43), superior parietal lobule (5), inferior parietal lobule (39-angular gyrus, 40), precuneus (7), intraparietal sulcus occipital lobe: primary visual cortex (17), cuneus, lingual gyrus, 18, 19 (18 and 19 span whole lobe) temporal lobe: transverse temporal gyrus (41-42-primary auditory cortex), superior temporal gyrus (38, 22-Wernicke's area), middle temporal gyrus (21), inferior temporal gyrus (20), fusiform gyrus (36, 37) limbic lobe/fornicate gyrus: cingulate cortex/cingulate gyrus, anterior cingulate (24, 32, 33), posterior cingulate (23, 31), isthmus (26, 29, 30), parahippocampal gyrus (piriform cortex, 25, 27, 35), entorhinal cortex (28, 34) subcortical/insular cortex: rhinencephalon, olfactory bulb, corpus callosum, lateral ventricles, septum pellucidum, ependyma, internal capsule, corona radiata, external capsule hippocampal formation: dentate gyrus, hippocampus, subiculum basal ganglia: striatum (caudate nucleus, putamen), lentiform nucleus (putamen, globus pallidus), claustrum, extreme capsule, amygdala, nucleus accumbens Some categorizations are approximations, and some Brodmann areas span gyri.