Editing Entorhinal cortex (section)

==Function==
===Neuron information processing===
In 2005, it was discovered that entorhinal cortex contains a [[Cognitive map|neural map]] of the spatial environment in rats.<ref name="Hafting">{{cite journal |vauthors=Hafting T, Fyhn M, Molden S, Moser M, Moser E |s2cid=4405184 |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 |bibcode=2005Natur.436..801H}}</ref> In 2014, John O'Keefe, May-Britt Moser and Edvard Moser received the [[Nobel Prize in Physiology or Medicine]], partly because of this discovery.<ref>{{cite web|title=Overview of Nobel Prize laureates in Physiology or Medicine|url=https://www.nobelprize.org/nobel_prizes/medicine/laureates/}}</ref>

In rodents, neurons in the lateral entorhinal cortex exhibit little spatial selectivity,<ref>{{cite journal |vauthors=Hargreaves E, Rao G, Lee I, Knierim J |s2cid=24399770 |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|bibcode = 2005Sci...308.1792H }}</ref> whereas neurons of the medial entorhinal cortex (MEC), exhibit multiple "place fields" that are arranged in a 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 name="Hafting" /><ref>{{cite journal |vauthors=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 |bibcode=2004Sci...305.1258F|doi-access= }}</ref>

The same group of researchers has found speed cells in the medial entorhinal cortex of rats. The speed of movement is translated from proprioceptive information and is represented as firing rates in these cells. The cells are known to fire in correlation to future speed of the rodent.<ref name="Kropff">{{cite journal |author1=Kropff Em |author2=Carmichael J E |author3=Moser M-B |author4=Moser E-I |s2cid=4404374 | year = 2015 | title = Speed cells in the medial entorhinal cortex | journal = Nature | volume = 523 |issue=7561 | pages = 419–424 | doi = 10.1038/nature14622 |pmid=26176924 |bibcode = 2015Natur.523..419K |hdl=11336/10493 |hdl-access=free }}</ref>

Recently, a general theory has been proposed to elucidate the function of the [[reelin]] positive cells in the layer II of the entorhinal cortex. According to this concept, these cells would be generally organized into 1-dimensional ring attractors, and in the ''medial'' (in humans: ''posteromedial'') portion, would function as [[grid cells]] (anatomically: stellate cells) while in ''lateral'' (in humans: ''anterolateral'') portion, where they appear as fan cells, would enable the encoding of new episodic memories.<ref>{{cite journal | vauthors = Kovács KA | title = Episodic Memories: How do the Hippocampus and the Entorhinal Ring Attractors Cooperate to Create Them? | journal = Frontiers in Systems Neuroscience | volume = 14 | page = 68 | date = September 2020 | doi = 10.3389/fnsys.2020.559186 | pmid = 33013334 | pmc = 7511719 | doi-access = free }}</ref> This concept is underscored by the fact that fan cells of the entorhinal cortex are indispensable for the formation of episodic-like memories in rodents.<ref>{{cite journal |vauthors=Vandrey B, Garden DL, Ambrozova V, McClure C, Nolan MF, Ainge JA | title = Fan cells in layer 2 of the lateral entorhinal cortex are critical for episodic-like memory.  | journal = Current Biology | volume = 30 | pages = 169–175.e5 | date = January 2020 | issue = 1 | doi = 10.1016/j.cub.2019.11.027 | pmid = 31839450 | pmc = 6947484 | doi-access = free }}</ref>

[[Single-unit recording]] of neurons in humans playing [[video game]]s find path cells in the EC, the activity of which indicates whether a person is taking a clockwise or counterclockwise path. Such EC "direction" path cells show this directional activity irrespective of the location of where a person experiences themselves, which contrasts them to place cells in the hippocampus, which are activated by specific locations.<ref name="Jacobs">{{cite journal |vauthors=Jacobs J, Kahana MJ, Ekstrom AD, Mollison MV, Fried I | year = 2010 | title = A sense of direction in human entorhinal cortex | journal = Proc Natl Acad Sci U S A | volume = 107 | issue = 14| pages = 6487–6492 | doi = 10.1073/pnas.0911213107 | pmid = 20308554 | pmc=2851993|bibcode = 2010PNAS..107.6487J | doi-access = free }}</ref>

EC neurons process general information such as directional activity in the environment, which contrasts to that of the hippocampal neurons, which usually encode information about specific places. This suggests that EC encodes general properties about current contexts that are then used by hippocampus to create unique representations from combinations of these properties.<ref name="Jacobs"/>

Research generally highlights a useful distinction in which the medial entorhinal cortex (MEC) mainly supports processing of space,<ref>{{Cite journal|title=Cellular mechanisms of spatial navigation in the medial entorhinal cortex|journal=Nature|volume=16|issue=3|pages=325–331|doi=10.1038/nn.3340|pmid=23396102|year=2013|last1=Schmidt-Hieber|first1=Christoph|last2=Häusser|first2=Michael|s2cid=13774938}}</ref> whereas the lateral entorhinal cortex (LEC) mainly supports the processing of time.<ref name=":0" /> 

The MEC exhibits a strong ~8 Hz [[Neural oscillation|rhythmic neural activity]] known as [[Theta wave|theta]]. Alterations in the neural activity across the brain region results in an observed "[[traveling wave]]" phenomena across the MEC long-axis, similar to that of the [[hippocampus]],<ref>{{cite journal |last1=Lubenov |first1=Evgueniy V. |last2=Siapas |first2=Athanassios G. |s2cid=4429491 |title=Hippocampal theta oscillations are travelling waves |journal=Nature |date=17 May 2009 |volume=459 |issue=7246 |pages=534–539 |doi=10.1038/nature08010|pmid=19489117 |bibcode=2009Natur.459..534L |url=https://authors.library.caltech.edu/14755/1/Lubenov2009p4508Nature.pdf }}</ref> due to asymmetric theta oscillations.<ref name="pmid32057292">{{cite journal |vauthors=Hernández-Pérez JJ, Cooper KW, Newman EL| title=Medial entorhinal cortex activates in a traveling wave in the rat. | journal=eLife | year= 2020 | volume= 9 | pmid=32057292 | doi=10.7554/eLife.52289 | pmc=7046467 | doi-access=free }} </ref> The underlying cause of these phase shifts and their waveform changes is unknown. 

Individual variation in the volume of EC is linked to taste perception. People with a larger EC in the left hemisphere found [[quinine]], the source of bitterness in [[tonic water]], less bitter.<ref>{{cite journal |vauthors=Hwang LD, Strike LT, Couvy-Duchesne B, de Zubicaray GI, McMahon K, Bresline PA, Reed DR, Martin NG, Wright MJ | year = 2019 | title = Associations between brain structure and perceived intensity of sweet and bitter tastes | journal = Behav. Brain Res. | volume = 2 |issue=363 | pages = 103–108 | doi = 10.1016/j.bbr.2019.01.046 |pmid= 30703394 | pmc = 6470356 }}</ref>