Independent delta/theta rhythms in the human hippocampus and entorhinal cortex

Theta oscillations in the medial temporal lobe (MTL) of mammals are involved in various functions such as spatial navigation, sensorimotor integration, and cognitive processing. While the theta rhythm was originally assumed to originate in the medial septum, more recent studies suggest autonomous th...

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Authors: Mormann, Florian, Osterhage, Hannes, Andrzejak, Ralph Gregor, Weber, Bernd, Fernández, Guillén, Fell, Juerguen, Elger, Christian E., Lehnertz, Klaus
Format: article
Status:Published version
Publication Date:2008
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10230/43593
Online Access:http://hdl.handle.net/10230/43593
http://dx.doi.org/10.3389/neuro.09.003.2008
Access Level:Open access
Keyword:Medial temporal lobe
Intracranial EEG
Oscillations
Synchronization
Wavelet
Phase precession
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spelling Independent delta/theta rhythms in the human hippocampus and entorhinal cortexMormann, FlorianOsterhage, HannesAndrzejak, Ralph GregorWeber, BerndFernández, GuillénFell, JuerguenElger, Christian E.Lehnertz, KlausMedial temporal lobeIntracranial EEGOscillationsSynchronizationWaveletPhase precessionTheta oscillations in the medial temporal lobe (MTL) of mammals are involved in various functions such as spatial navigation, sensorimotor integration, and cognitive processing. While the theta rhythm was originally assumed to originate in the medial septum, more recent studies suggest autonomous theta generation in the MTL. Although coherence between entorhinal and hippocampal theta activity has been found to infl uence memory formation, it remains unclear whether these two structures can generate theta independently. In this study we analyzed intracranial electroencephalographic (EEG) recordings from 22 patients with unilateral hippocampal sclerosis undergoing presurgical evaluation prior to resection of the epileptic focus. Using a wavelet-based, frequency-band-specifi c measure of phase synchronization, we quantifi ed synchrony between 10 different recording sites along the longitudinal axis of the hippocampal formation in the non-epileptic brain hemisphere. We compared EEG synchrony between adjacent recording sites (i) within the entorhinal cortex, (ii) within the hippocampus, and (iii) between the hippocampus and entorhinal cortex. We observed a signifi cant interregional gap in synchrony for the delta and theta band, indicating the existence of independent delta/theta rhythms in different subregions of the human MTL. The interaction of these rhythms could represent the temporal basis for the information processing required for mnemonic encoding and retrieval.This work was supported by the Intramural Research Fund BONFOR of the University of Bonn and the 6th Framework Programme of the European Commission (Marie Curie OIF 040445).Frontiers202020202008info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfapplication/pdfhttp://hdl.handle.net/10230/43593http://dx.doi.org/10.3389/neuro.09.003.2008reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésFrontiers in Human Neuroscience. 2011;15(3);2-3info:eu-repo/grantAgreement/EC/FP6/040445Copyright © 2008 Mormann, Osterhage, Andrzejak, Weber, Fernández, Fell, Elger and Lehnertz. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.info:eu-repo/semantics/openAccessoai:recercat.cat:10230/435932026-05-29T05:05:01Z
dc.title.none.fl_str_mv Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
title Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
spellingShingle Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
Mormann, Florian
Medial temporal lobe
Intracranial EEG
Oscillations
Synchronization
Wavelet
Phase precession
title_short Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
title_full Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
title_fullStr Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
title_full_unstemmed Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
title_sort Independent delta/theta rhythms in the human hippocampus and entorhinal cortex
dc.creator.none.fl_str_mv Mormann, Florian
Osterhage, Hannes
Andrzejak, Ralph Gregor
Weber, Bernd
Fernández, Guillén
Fell, Juerguen
Elger, Christian E.
Lehnertz, Klaus
author Mormann, Florian
author_facet Mormann, Florian
Osterhage, Hannes
Andrzejak, Ralph Gregor
Weber, Bernd
Fernández, Guillén
Fell, Juerguen
Elger, Christian E.
Lehnertz, Klaus
author_role author
author2 Osterhage, Hannes
Andrzejak, Ralph Gregor
Weber, Bernd
Fernández, Guillén
Fell, Juerguen
Elger, Christian E.
Lehnertz, Klaus
author2_role author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Medial temporal lobe
Intracranial EEG
Oscillations
Synchronization
Wavelet
Phase precession
topic Medial temporal lobe
Intracranial EEG
Oscillations
Synchronization
Wavelet
Phase precession
description Theta oscillations in the medial temporal lobe (MTL) of mammals are involved in various functions such as spatial navigation, sensorimotor integration, and cognitive processing. While the theta rhythm was originally assumed to originate in the medial septum, more recent studies suggest autonomous theta generation in the MTL. Although coherence between entorhinal and hippocampal theta activity has been found to infl uence memory formation, it remains unclear whether these two structures can generate theta independently. In this study we analyzed intracranial electroencephalographic (EEG) recordings from 22 patients with unilateral hippocampal sclerosis undergoing presurgical evaluation prior to resection of the epileptic focus. Using a wavelet-based, frequency-band-specifi c measure of phase synchronization, we quantifi ed synchrony between 10 different recording sites along the longitudinal axis of the hippocampal formation in the non-epileptic brain hemisphere. We compared EEG synchrony between adjacent recording sites (i) within the entorhinal cortex, (ii) within the hippocampus, and (iii) between the hippocampus and entorhinal cortex. We observed a signifi cant interregional gap in synchrony for the delta and theta band, indicating the existence of independent delta/theta rhythms in different subregions of the human MTL. The interaction of these rhythms could represent the temporal basis for the information processing required for mnemonic encoding and retrieval.
publishDate 2008
dc.date.none.fl_str_mv 2008
2020
2020
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10230/43593
http://dx.doi.org/10.3389/neuro.09.003.2008
url http://hdl.handle.net/10230/43593
http://dx.doi.org/10.3389/neuro.09.003.2008
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Frontiers in Human Neuroscience. 2011;15(3);2-3
info:eu-repo/grantAgreement/EC/FP6/040445
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Frontiers
publisher.none.fl_str_mv Frontiers
dc.source.none.fl_str_mv reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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