How informative are spatial CA3 representations established by the dentate gyrus?

In the mammalian hippocampus, the dentate gyrus (DG) is characterized by sparse and powerful unidirectional projections to CA3 pyramidal cells, the so-called mossy fibers. Mossy fiber synapses appear to duplicate, in terms of the information they convey, what CA3 cells already receive from entorhina...

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Autores principales:	Erika Cerasti, Alessandro Treves
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2010
Materias:	Biology (General) QH301-705.5
Acceso en línea:	https://doaj.org/article/559099b5af0c4b7e90e361fc1e08e155
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spelling	oai:doaj.org-article:559099b5af0c4b7e90e361fc1e08e1552021-12-02T19:58:27ZHow informative are spatial CA3 representations established by the dentate gyrus?1553-734X1553-735810.1371/journal.pcbi.1000759https://doaj.org/article/559099b5af0c4b7e90e361fc1e08e1552010-04-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/20454678/?tool=EBIhttps://doaj.org/toc/1553-734Xhttps://doaj.org/toc/1553-7358In the mammalian hippocampus, the dentate gyrus (DG) is characterized by sparse and powerful unidirectional projections to CA3 pyramidal cells, the so-called mossy fibers. Mossy fiber synapses appear to duplicate, in terms of the information they convey, what CA3 cells already receive from entorhinal cortex layer II cells, which project both to the dentate gyrus and to CA3. Computational models of episodic memory have hypothesized that the function of the mossy fibers is to enforce a new, well-separated pattern of activity onto CA3 cells, to represent a new memory, prevailing over the interference produced by the traces of older memories already stored on CA3 recurrent collateral connections. Can this hypothesis apply also to spatial representations, as described by recent neurophysiological recordings in rats? To address this issue quantitatively, we estimate the amount of information DG can impart on a new CA3 pattern of spatial activity, using both mathematical analysis and computer simulations of a simplified model. We confirm that, also in the spatial case, the observed sparse connectivity and level of activity are most appropriate for driving memory storage-and not to initiate retrieval. Surprisingly, the model also indicates that even when DG codes just for space, much of the information it passes on to CA3 acquires a non-spatial and episodic character, akin to that of a random number generator. It is suggested that further hippocampal processing is required to make full spatial use of DG inputs.Erika CerastiAlessandro TrevesPublic Library of Science (PLoS)articleBiology (General)QH301-705.5ENPLoS Computational Biology, Vol 6, Iss 4, p e1000759 (2010)
institution	DOAJ
collection	DOAJ
language	EN
topic	Biology (General) QH301-705.5
spellingShingle	Biology (General) QH301-705.5 Erika Cerasti Alessandro Treves How informative are spatial CA3 representations established by the dentate gyrus?
description	In the mammalian hippocampus, the dentate gyrus (DG) is characterized by sparse and powerful unidirectional projections to CA3 pyramidal cells, the so-called mossy fibers. Mossy fiber synapses appear to duplicate, in terms of the information they convey, what CA3 cells already receive from entorhinal cortex layer II cells, which project both to the dentate gyrus and to CA3. Computational models of episodic memory have hypothesized that the function of the mossy fibers is to enforce a new, well-separated pattern of activity onto CA3 cells, to represent a new memory, prevailing over the interference produced by the traces of older memories already stored on CA3 recurrent collateral connections. Can this hypothesis apply also to spatial representations, as described by recent neurophysiological recordings in rats? To address this issue quantitatively, we estimate the amount of information DG can impart on a new CA3 pattern of spatial activity, using both mathematical analysis and computer simulations of a simplified model. We confirm that, also in the spatial case, the observed sparse connectivity and level of activity are most appropriate for driving memory storage-and not to initiate retrieval. Surprisingly, the model also indicates that even when DG codes just for space, much of the information it passes on to CA3 acquires a non-spatial and episodic character, akin to that of a random number generator. It is suggested that further hippocampal processing is required to make full spatial use of DG inputs.
format	article
author	Erika Cerasti Alessandro Treves
author_facet	Erika Cerasti Alessandro Treves
author_sort	Erika Cerasti
title	How informative are spatial CA3 representations established by the dentate gyrus?
title_short	How informative are spatial CA3 representations established by the dentate gyrus?
title_full	How informative are spatial CA3 representations established by the dentate gyrus?
title_fullStr	How informative are spatial CA3 representations established by the dentate gyrus?
title_full_unstemmed	How informative are spatial CA3 representations established by the dentate gyrus?
title_sort	how informative are spatial ca3 representations established by the dentate gyrus?
publisher	Public Library of Science (PLoS)
publishDate	2010
url	https://doaj.org/article/559099b5af0c4b7e90e361fc1e08e155
work_keys_str_mv	AT erikacerasti howinformativearespatialca3representationsestablishedbythedentategyrus AT alessandrotreves howinformativearespatialca3representationsestablishedbythedentategyrus
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How informative are spatial CA3 representations established by the dentate gyrus?

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