Entorhinal cortex 9667 221881885 2008-06-26T14:41:36Z 69.70.161.66 /* Anatomy */ {{Infobox Brain| Name = Entorhinal cortex | Latin = | GraySubject = | GrayPage = | Image = Gray727-Brodman.png | Caption = Medial surface. (Entorhinal cortex approximately maps to areas 28 and 34, at lower left.) | Image2 = | Caption2 = | Width = 300 | IsPartOf = [[Temporal lobe]]| Components = | Artery = [[Posterior cerebral artery|Posterior cerebral]] <br/> [[Choroid artery|Choroid]]| Vein = [[Inferior striate vein|Inferior striate]]| BrainInfoType = hier | BrainInfoNumber = 150 | MeshName = Entorhinal+Cortex | MeshNumber = A08.186.211.577.710.225 | }} The '''entorhinal cortex (EC)''' is an important [[memory]] center in the [[brain]]. The EC forms the main input to the [[hippocampus]] and is responsible for the pre-processing (familiarity) of the input signals. In the reflex [[nictitating membrane]] response of classical trace conditioning, the association of impulses from the [[eye]] and the [[ear]] occurs in the entorhinal cortex. The [[EC-hippocampus system]] plays an important role in [[memory consolidation]] and [[memory optimization]] in [[sleep]]. Entorhinal cortex is one of the first areas to be affected in [[Alzheimer's Disease]], and one of the first symptoms is impaired sense of direction. In 2005, it was discovered that entorhinal cortex contains a neural map of the spatial environment.<ref name="Hafting">{{cite journal |author=Hafting T, Fyhn M, Molden S, Moser M, Moser E |title=Microstructure of a spatial map in the entorhinal cortex |journal=Nature |volume=436 |issue=7052 |pages=801–6 |year=2005 |pmid=15965463 | doi = 10.1038/nature03721 <!--Retrieved from PMID by DOI bot-->}}</ref> The entorhinal cortex shows a modular organization, with different properties and connections in different areas. Neurons in the lateral entorhinal cortex exhibit little spatial selectivity<ref>{{cite journal |author=Hargreaves E, Rao G, Lee I, Knierim J |title=Major dissociation between medial and lateral entorhinal input to dorsal hippocampus |journal=Science |volume=308 |issue=5729 |pages=1792–4 |year=2005 |pmid=15961670 |doi=10.1126/science.1110449}}</ref>, whereas neurons of the medial entorhinal (MEA) cortex exhibit multiple "place fields" that are arranged in an hexagonal pattern, and are therefore called "[[grid cells]]." These fields and spacing between fields increase from the dorso-lateral MEA to the ventro-medial MEA.<ref>{{cite journal |author=Fyhn M, Molden S, Witter M, Moser E, Moser M |title=Spatial representation in the entorhinal cortex |journal=Science |volume=305 |issue=5688 |pages=1258–64 |year=2004 |pmid=15333832 |doi=10.1126/science.1099901}}</ref><ref name="Hafting"> </ref> == Anatomy == In rodents, the EC is located at the [[caudal]] end of the [[temporal lobe]]. In primates it is located at the [[rostral]] end of the temporal lobe and stretches dorsolaterally. It is usually divided into [[medial]] and [[Human anatomical terms#Anatomical directions|lateral]] regions with three bands with distinct properties and connectivity running perpendicular across the whole area. A distinguishing characteristic of the EC is the lack of cell bodies where layer IV should be; this layer is called the ''lamina dissecans''. == Inputs and outputs == The superficial layers - layers II and III - of EC project to the [[dentate gyrus]] and [[hippocampus]]: Layer II projects primarily to [[dentate gyrus]] and hippocampal region CA3; layer III projects primarily to hippocampal region CA1 and the [[subiculum]]. These layers receive input from other cortical areas, especially associational, [[Perirhinal cortex|perirhinal]], and [[Parahippocampal gyrus|parahippocampal]] cortices, as well as [[prefrontal cortex]]. EC as a whole, therefore, receives highly-processed input from every sensory modality, as well as input relating to ongoing cognitive processes, though it should be stressed that, within EC, this information remains at least partially segregated. The deep layers, especially layer V, receive one of the three main outputs of the [[hippocampus]] and, in turn, reciprocate connections from other cortical areas that project to superficial EC. ==Brodmann's areas== * [[Brodmann area 28]] is known as the "area entorhinalis" * [[Brodmann area 34]] is known as the "area entorhinalis dorsalis" ==References== {{Reflist|2}} ==External links== * [http://www.ramsoy.dk/images/Brodmann_templobe.jpg Diagram at ramsoy.dk] * {{BrainMaps|Entorhinal%20cortex|Entorhinal cortex}} {{Prosencephalon}} {{Papez circuit}} [[Category:Neuroanatomy]] [[Category:Limbic system]] [[Category:Cerebrum]] [[it:Corteccia entorinale]] [[nl:Entorinale schors]] [[no:Entorhinal cortex]] [[pl:Kora śródwechowa]]