Retrosplenial cortex

{{expand section|date=November 2014}}

There is large variation in the region's size across different species. In humans it comprises roughly 0.3% of the entire cortical surface whereas in rabbits it is at least 10%{{cite book|last1=notes|first1=K. Brodmann; translated with editorial|last2=Garey|first2=an introduction by Laurence J.|title=Brodmann's Localisation in the cerebral cortex the principles of comparative localisation in the cerebral cortex based on cytoarchitectonics|date=2006|publisher=Springer|location=New York|isbn=978-0-387-26919-1|edition=3rd}} and in rats it extends for more than half the cerebrum dorso-ventrally, making it one of the largest cortical regions.

On the basis of its microscopic cellular structure it is divided into dysgranular (area 30) and granular (area 29) regions. These have been divided into four areas: 29l, 29m, 30l, and 30m.{{cite journal |last=Vogt |first=Brent A. |last2=Rosene |first2=Douglas L. |date=2023 |title=Comparison of monkey and human retrosplenial neurocytology |journal=Journal of Comparative Neurology |volume=531 |issue=18 |pages=2044–2061 |doi=10.1002/cne.25561 |issn=0021-9967}} It has dense reciprocal projections with the visual cortex, postsubiculum (also known as dorsal presubiculum) and with anterior thalamic nuclei and the hippocampus.{{Cite journal|last1=Sugar|first1=Jorgen|last2=Witter|first2=Menno P.|last3=van Strien|first3=Niels|last4=Cappaert|first4=Natalie|date=2011|title=The Retrosplenial Cortex: Intrinsic Connectivity and Connections with the (Para)Hippocampal Region in the Rat. An Interactive Connectome|journal=Frontiers in Neuroinformatics|language=English|volume=5|page=7|doi=10.3389/fninf.2011.00007|issn=1662-5196|pmc=3147162|pmid=21847380|doi-access=free}}

Neurophysiological studies of retrosplenial cortex have mainly been done in rats. Early work showed that around 8.5% of neurons in the retrosplenial cortex are head direction cells while other neurons have correlated with movement parameters such as spatial location and running speed.{{cite journal|last1=Chen|first1=Longtang L.|last2=Lin|first2=Lie-Huey|last3=Green|first3=Edward J.|last4=Barnes|first4=Carol A.|last5=McNaughton|first5=Bruce L.|title=Head-direction cells in the rat posterior cortex|journal=Experimental Brain Research|date=September 1994|volume=101|issue=1|pages=8–23|doi=10.1007/BF00243212|pmid=7843305|s2cid=25125371}}{{cite journal|last1=Cho|first1=J|last2=Sharp|first2=PE|title=Head direction, place, and movement correlates for cells in the rat retrosplenial cortex.|journal=Behavioral Neuroscience|date=February 2001|volume=115|issue=1|pages=3–25|pmid=11256450|doi=10.1037/0735-7044.115.1.3}} Recent studies have shown that retrosplenial neuronal activity reflects multiple parameters simultaneously including which environment the animal is currently in, its spatial position in the environment,{{Cite journal|last1=Miller|first1=Adam M P|last2=Serrichio|first2=Anna C|last3=Smith|first3=David M|date=2021-05-01|title=Dual-Factor Representation of the Environmental Context in the Retrosplenial Cortex|url=https://doi.org/10.1093/cercor/bhaa386|journal=Cerebral Cortex|volume=31|issue=5|pages=2720–2728|doi=10.1093/cercor/bhaa386|issn=1047-3211|pmc=8023839|pmid=33386396}} its current head direction and running speed, as well as whether the animal is turning{{Cite journal|title = Retrosplenial cortex maps the conjunction of internal and external spaces|journal = Nature Neuroscience|date = 2015-08-01|issn = 1546-1726|pmid = 26147532|pages = 1143–1151|volume = 18|issue = 8|doi = 10.1038/nn.4058|first1 = Andrew S.|last1 = Alexander|first2 = Douglas A.|last2 = Nitz|s2cid = 13211352}} or plans to turn in the future.{{Cite journal|last1=Miller|first1=Adam M.P.|last2=Mau|first2=William|last3=Smith|first3=David M.|date=June 2019|title=Retrosplenial Cortical Representations of Space and Future Goal Locations Develop with Learning|journal=Current Biology|language=en|volume=29|issue=12|pages=2083–2090.e4|doi=10.1016/j.cub.2019.05.034|pmc=6637961|pmid=31178316}} Many of these features of retrosplenial neurophysiology develop slowly as the animal learns to navigate within an environment, consistent with the idea that the retrosplenial cortex participates in the long-term storage of spatial memory.{{Cite journal|last1=Miller|first1=Adam M. P.|last2=Vedder|first2=Lindsey C.|last3=Law|first3=L. Matthew|last4=Smith|first4=David M.|date=2014-08-05|title=Cues, context, and long-term memory: the role of the retrosplenial cortex in spatial cognition|journal=Frontiers in Human Neuroscience|volume=8|page=586|doi=10.3389/fnhum.2014.00586|issn=1662-5161|pmc=4122222|pmid=25140141|doi-access=free}}

In humans, fMRI studies implicate the retrosplenial cortex in a wide range of cognitive functions including episodic memory, navigation, imagining future events and processing scenes more generally.{{cite journal|last1=Spreng|first1=R. Nathan|last2=Mar|first2=Raymond A.|last3=Kim|first3=Alice S. N.|title=The Common Neural Basis of Autobiographical Memory, Prospection, Navigation, Theory of Mind, and the Default Mode: A Quantitative Meta-analysis|journal=Journal of Cognitive Neuroscience|date=March 2009|volume=21|issue=3|pages=489–510|doi=10.1162/jocn.2008.21029|pmid=18510452|citeseerx=10.1.1.454.7288|s2cid=2069491}} Rodent studies suggest the region is important for using surrounding visual cues to carry out these tasks.{{cite journal|last1=Pothuizen|first1=Helen H. J.|last2=Davies|first2=Moira|last3=Albasser|first3=Mathieu M.|last4=Aggleton|first4=John P.|last5=Vann|first5=Seralynne D.|title=Granular and dysgranular retrosplenial cortices provide qualitatively different contributions to spatial working memory: evidence from immediate-early gene imaging in rats|journal=European Journal of Neuroscience|date=September 2009|volume=30|issue=5|pages=877–888|doi=10.1111/j.1460-9568.2009.06881.x|pmid=19712100|s2cid=24868413}}{{cite journal |last1=Czajkowski |first1=R. |last2=Jayaprakash |first2=B. |last3=Wiltgen |first3=B. |last4=Rogerson |first4=T. |last5=Guzman-Karlsson |first5=M. C. |last6=Barth |first6=A. L. |author-link6=Alison Barth |last7=Trachtenberg |first7=J. T. |last8=Silva |first8=A. J. |date=27 May 2014 |title=Encoding and storage of spatial information in the retrosplenial cortex |journal=Proceedings of the National Academy of Sciences |volume=111 |issue=23 |pages=8661–8666 |bibcode=2014PNAS..111.8661C |doi=10.1073/pnas.1313222111 |pmc=4060653 |pmid=24912150 |doi-access=free}}{{cite journal|last1=Yoder|first1=Ryan M.|last2=Clark|first2=Benjamin J.|last3=Taube|first3=Jeffrey S.|title=Origins of landmark encoding in the brain|journal=Trends in Neurosciences|date=November 2011|volume=34|issue=11|pages=561–571|doi=10.1016/j.tins.2011.08.004|pmid=21982585|pmc=3200508}} Retrosplenial cortex is particularly responsive to permanent, non-moving environmental landmarks{{cite journal|last1=Auger|first1=Stephen D.|last2=Mullally|first2=Sinéad L.|last3=Maguire|first3=Eleanor A.|last4=Baker|first4=Chris I.|title=Retrosplenial Cortex Codes for Permanent Landmarks|journal=PLOS ONE|date=17 August 2012|volume=7|issue=8|pages=e43620|doi=10.1371/journal.pone.0043620|pmid=22912894|bibcode=2012PLoSO...743620A|pmc=3422332|doi-access=free}}{{cite journal|last1=Auger|first1=Stephen D.|last2=Maguire|first2=Eleanor A.|title=Assessing the mechanism of response in the retrosplenial cortex of good and poor navigators|journal=Cortex|date=November 2013|volume=49|issue=10|pages=2904–2913|doi=10.1016/j.cortex.2013.08.002|pmid=24012136|pmc=3878422}}and is also implicated in using them to make spatial judgements.{{cite journal|last1=Committeri|first1=Giorgia|last2=Galati|first2=Gaspare|last3=Paradis|first3=Anne-Lise|last4=Pizzamiglio|first4=Luigi|last5=Berthoz|first5=Alain|last6=LeBihan|first6=Denis|title=Reference Frames for Spatial Cognition: Different Brain Areas are Involved in Viewer-, Object-, and Landmark-Centered Judgments About Object Location|journal=Journal of Cognitive Neuroscience|date=November 2004|volume=16|issue=9|pages=1517–1535|doi=10.1162/0898929042568550|pmid=15601516|s2cid=15743957}}{{cite journal|last1=Galati|first1=Gaspare|last2=Pelle|first2=Gina|last3=Berthoz|first3=Alain|last4=Committeri|first4=Giorgia|title=Multiple reference frames used by the human brain for spatial perception and memory|journal=Experimental Brain Research|date=26 February 2010|volume=206|issue=2|pages=109–120|doi=10.1007/s00221-010-2168-8|pmid=20186405|s2cid=23546010}} A review in 2023 suggested its function was "spatial navigation and localization of personally relevant objects".

It has also been suggested that retrosplenial cortex may translate between egocentric (self-centred) and allocentric (world-centred) spatial information, based upon its anatomical location between the hippocampus (where there are allocentric place cell representations) and the parietal lobe (which integrates egocentric sensory information).{{cite journal|last1=Byrne|first1=Patrick|last2=Becker|first2=Suzanna|last3=Burgess|first3=Neil|title=Remembering the past and imagining the future: A neural model of spatial memory and imagery|journal=Psychological Review|date=2007|volume=114|issue=2|pages=340–375|doi=10.1037/0033-295X.114.2.340|pmid=17500630|pmc=2678675}}{{cite journal|last1=Marchette|first1=Steven|last2=Vass|first2=Lindsay|last3=Ryan|first3=Jack|last4=Epstein|first4=Russell|title=Anchoring the neural compass: Coding of local spatial reference frames in human medial parietal lobe|journal=Nature Neuroscience|date=2014|volume=17|issue=11|pages=1598–1606|doi=10.1038/nn.3834|pmid=25282616|pmc=4309016}}

Competitors in the World Memory Championships are able to perform outstanding feats of memory and show increased fMRI activation in their retrosplenial cortex than normal controls when doing so.{{cite journal|last1=Maguire|first1=Eleanor A.|last2=Valentine|first2=Elizabeth R.|last3=Wilding|first3=John M.|last4=Kapur|first4=Narinder|title=Routes to remembering: the brains behind superior memory|journal=Nature Neuroscience|date=16 December 2002|volume=6|issue=1|pages=90–95|doi=10.1038/nn988|pmid=12483214|s2cid=13921255}} This is thought to be due to their use of a spatial learning strategy or mnemonic device known as the method of loci.

The region also displays slow-wave theta rhythmicity{{cite journal|last1=Destrade|first1=C|last2=Ott|first2=T|title=Is a retrosplenial (cingulate) pathway involved in the mediation of high frequency hippocampal rhythmical slow activity (theta)?|journal=Brain Research|date=2 December 1982|volume=252|issue=1|pages=29–37|pmid=6293657|doi=10.1016/0006-8993(82)90975-1|s2cid=22294467}} and when people retrieve autobiographical memories, there is theta band interaction between the retrosplenial cortex and the medial temporal lobe.{{cite journal|last1=Foster|first1=B. L.|last2=Kaveh|first2=A.|last3=Dastjerdi|first3=M.|last4=Miller|first4=K. J.|last5=Parvizi|first5=J.|title=Human Retrosplenial Cortex Displays Transient Theta Phase Locking with Medial Temporal Cortex Prior to Activation during Autobiographical Memory Retrieval|journal=Journal of Neuroscience|date=19 June 2013|volume=33|issue=25|pages=10439–10446|doi=10.1523/JNEUROSCI.0513-13.2013|pmid=23785155|pmc=3685837}}

The retrosplenial cortex is one of several brain areas that produces both an anterograde and retrograde amnesia when damaged.{{cite journal|last1=Valenstein|first1=E|last2=Bowers|first2=D|last3=Verfaellie|first3=M|last4=Heilman|first4=KM|last5=Day|first5=A|last6=Watson|first6=RT|title=Retrosplenial amnesia.|journal=Brain: A Journal of Neurology|date=December 1987|volume=110|pages=1631–46|pmid=3427404|issue=6|doi=10.1093/brain/110.6.1631|doi-access=free}} People with lesions involving the retrosplenial cortex also display a form of topographical disorientation whereby they can recognise and identify environmental landmarks, but are unable to use them to orientate themselves.

The retrosplenial cortex is one of the first regions to undergo pathological changes in Alzheimer's disease and its prodromal phase of mild cognitive impairment.{{cite journal|last1=Pengas|first1=George|last2=Hodges|first2=John R.|last3=Watson|first3=Peter|last4=Nestor|first4=Peter J.|title=Focal posterior cingulate atrophy in incipient Alzheimer's disease|journal=Neurobiology of Aging|date=January 2010|volume=31|issue=1|pages=25–33|doi=10.1016/j.neurobiolaging.2008.03.014|pmid=18455838|s2cid=34598530}}{{cite journal|last1=Pengas|first1=George|last2=Williams|first2=Guy B.|last3=Acosta-Cabronero|first3=Julio|last4=Ash|first4=Tom W. J.|last5=Hong|first5=Young T.|last6=Izquierdo-Garcia|first6=David|last7=Fryer|first7=Tim D.|last8=Hodges|first8=John R.|last9=Nestor|first9=Peter J.|title=Retrosplenial Cortex (BA 29) Volumes in Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease|journal=Frontiers in Aging Neuroscience|date=2012|volume=4|pages=17|doi=10.3389/fnagi.2012.00017|pmid=22783190|pmc=3389330|doi-access=free}}{{cite journal|last1=Tan|first1=Rachel H.|last2=Wong|first2=Stephanie|last3=Hodges|first3=John R.|last4=Halliday|first4=Glenda M.|last5=Hornberger|first5=Michael|title=Retrosplenial Cortex (BA 29) Volumes in Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease|journal=Dementia and Geriatric Cognitive Disorders|date=2013|volume=35|issue=3–4|pages=177–182|doi=10.1159/000346392|pmid=23406695|s2cid=45735133|url=https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12293/SOURCE01?view=true|hdl=1959.4/53598|hdl-access=free}}

There are also experimental findings showing that layer 5 of the retrosplenial cortex is likely responsible for dissociative states of consciousness in mammals.{{cite journal|journal=Nature|date=September 2020|title=Deep posteromedial cortical rhythm in dissociation|last1=Vesuna|first1=S|first2=I|last2=Kauvar|volume=586|issue=7827|pages=87–94|display-authors=1|doi=10.1038/s41586-020-2731-9|pmid=32939091|s2cid=221769346|pmc=7553818|bibcode=2020Natur.586...87V}}

File:Brodmann Cytoarchitectonics 29.png|Brodmann area 29

File:Brodmann Cytoarchitectonics 30.png|Brodmann area 30

{{Commons category|Retrosplenial cortex}}

{{Telencephalon}}

Category:Cerebral cortex

Category:Medial surface of cerebral hemisphere