Subiculum

The subiculum got its name from Karl Friedrich Burdach in his three-volume work Vom Bau und Leben des Gehirns (Vol. 2, §199). He originally named it subiculum cornu ammonis and so associated it with the rest of the hippocampal subfields.

The subicular complex receives input from CA1 and entorhinal cortical layer III pyramidal neurons and is the main output of the hippocampus proper. The pyramidal neurons send projections to the nucleus accumbens, septal nuclei, prefrontal cortex, lateral hypothalamus, nucleus reuniens, mammillary nuclei, entorhinal cortex and amygdala.

The pyramidal neurons in the subiculum exhibit transitions between two modes of action potential output: bursting and single spiking.[http://www.neurocloud.org/ Donald C. Cooper], Sungkwon Chung, Nelson Spruston, "[http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0030175 Output-Mode Transitions Are Controlled by Prolonged Inactivation of Sodium Channels in Pyramidal Neurons of Subiculum]," PLoS Biology, 3(6):e175, 2005 June. The transitions between these two modes is thought to be important for routing information out of the hippocampus.

Four component areas have been described:{{cite web |url=http://atlas.brain-map.org |title = Allen Reference Atlases :: Atlas Viewer}} parasubiculum (adjacent to the parahippocampal gyrus), presubiculum, postsubiculum, and prosubiculum.

The parasubiculum contains grid cells,{{Cite journal|title = Grid cells in pre- and parasubiculum|journal = Nature Neuroscience|date = 2010-08-01|issn = 1546-1726|pmid = 20657591|pages = 987–994|volume = 13|issue = 8|doi = 10.1038/nn.2602|first1 = Charlotte N.|last1 = Boccara|first2 = Francesca|last2 = Sargolini|first3 = Veslemøy Hult|last3 = Thoresen|first4 = Trygve|last4 = Solstad|first5 = Menno P.|last5 = Witter|first6 = Edvard I.|last6 = Moser|first7 = May-Britt|last7 = Moser|s2cid = 7851286}} which are neurons responsive to movements in particular directions over particular distances.

The presubiculum is part of the posterior cortex corresponding to Brodmann area 27, and forms part of the cortical input to the entorhinal-hippocampal spatial/memory system.

The dorsal part of the presubiculum is more commonly known as the postsubiculum{{Cite journal|title = An autoradiographic study of the organization of the efferent connections of the hippocampal formation in the rat|journal = The Journal of Comparative Neurology|date = 1977-03-01|issn = 0021-9967|pmid = 65364|pages = 49–84|volume = 172|issue = 1|doi = 10.1002/cne.901720104|first1 = L. W.|last1 = Swanson|first2 = W. M.|last2 = Cowan|s2cid = 40742028}} and is of interest because it contains head direction cells, which are responsive to the facing direction of the head.{{Cite journal|title = Head-direction cells recorded from the postsubiculum in freely moving rats. I. Description and quantitative analysis|journal = The Journal of Neuroscience|date = 1990-02-01|issn = 0270-6474|pmid = 2303851|pmc = 6570151|pages = 420–435|volume = 10|issue = 2|first1 = J. S.|last1 = Taube|first2 = R. U.|last2 = Muller|first3 = J. B.|last3 = Ranck|doi = 10.1523/JNEUROSCI.10-02-00420.1990}}

Prosubiculum is a term often used in reference to monkey anatomy but rarely in rodents, referring to a region located between the CA1 region of the hippocampus and the subiculum, and distinguished by higher cell density and smaller cell sizes.

It is believed to play a role in some cases of human epilepsy.{{cite journal |vauthors=Knopp A, Frahm C, Fidzinski P, Witte OW, Behr J |title=Loss of GABAergic neurons in the subiculum and its functional implications in temporal lobe epilepsy |journal=Brain |volume=131 |issue=Pt 6 |pages=1516–27 |date=June 2008 |pmid=18504292 |doi=10.1093/brain/awn095 |doi-access= }}{{cite journal |author=Stafstrom CE |title=The role of the subiculum in epilepsy and epileptogenesis |journal=Epilepsy Curr |volume=5 |issue=4 |pages=121–9 |year=2005 |pmid=16151518 |pmc=1198740 |doi=10.1111/j.1535-7511.2005.00049.x }}

It has also been implicated in working memory{{cite journal |vauthors=Riegert C, Galani R, Heilig S, Lazarus C, Cosquer B, Cassel JC |title=Electrolytic lesions of the ventral subiculum weakly alter spatial memory but potentiate amphetamine-induced locomotion |journal=Behav. Brain Res. |volume=152 |issue=1 |pages=23–34 |date=June 2004 |pmid=15135966 |doi=10.1016/j.bbr.2003.09.011 |s2cid=1772748 }} and drug addiction.{{cite journal |vauthors=Martin-Fardon R, Ciccocioppo R, Aujla H, Weiss F |title=The dorsal subiculum mediates the acquisition of conditioned reinstatement of cocaine-seeking |journal=Neuropsychopharmacology |volume=33 |issue=8 |pages=1827–34 |date=July 2008 |pmid=17957218 |doi=10.1038/sj.npp.1301589 |doi-access=free }}

It has been suggested that the dorsal subiculum is involved in spatial relations, and the ventral subiculum regulates the hypothalamic-pituitary-adrenal axis.{{cite journal |author=O'Mara S |title=The subiculum: what it does, what it might do, and what neuroanatomy has yet to tell us |journal=J. Anat. |volume=207 |issue=3 |pages=271–82 |date=September 2005 |pmid=16185252 |pmc=1571536 |doi=10.1111/j.1469-7580.2005.00446.x }}

Rat studies indicate that lesioning of the subiculum decreases the spread of amyloid-beta in rat models of Alzheimer's disease. Alzheimer's disease pathology is thought to have prion-like properties. The disease tends to spread in characteristic sequence from the entorhinal cortex through the subiculum.{{cite journal|last=George|first=Sonia|author2=Annica Rönnbäck |author3=Gunnar K Gouras |author4=Géraldine H Petit |author5=Fiona Grueninger |author6=Bengt Winblad |author7=Caroline Graff |author8=Patrik Brundin |year=2014|title=Lesion of the subiculum reduces the spread of amyloid beta pathology to interconnected brain regions in a mouse model of Alzheimer's disease|journal=Acta Neuropathologica Communications|volume=2|issue=1|page=17|issn=2051-5960|doi=10.1186/2051-5960-2-17|pmid=24517102 |pmc=3932948 |doi-access=free }}

File:CajalHippocampus (modified).png|Basic circuit of the hippocampus

{{Reflist|2}}

• [http://www.anatomie.net/histowebatlas/m-426a.htm Photo]
• [http://edoc.hu-berlin.de/dissertationen/schubert-stephan-nicolas-2003-09-26/HTML/schubert_html_21d219b1.png Photo]
• {{BrainMaps|Subiculum}}

{{Hippocampal formation}}

{{Papez circuit}}

{{Authority control}}

Category:Hippocampus (brain)