Neuronal assembly detection and cell membership specification by principal component analysis

In 1949, Donald Hebb postulated that assemblies of synchronously activated neurons are the elementary units of information processing in the brain. Despite being one of the most influential theories in neuroscience, Hebb's cell assembly hypothesis only started to become testable in the past two...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:PloS one 2011-06, Vol.6 (6), p.e20996-e20996
Hauptverfasser: Lopes-dos-Santos, Vítor, Conde-Ocazionez, Sergio, Nicolelis, Miguel A L, Ribeiro, Sidarta T, Tort, Adriano B L
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
container_end_page e20996
container_issue 6
container_start_page e20996
container_title PloS one
container_volume 6
creator Lopes-dos-Santos, Vítor
Conde-Ocazionez, Sergio
Nicolelis, Miguel A L
Ribeiro, Sidarta T
Tort, Adriano B L
description In 1949, Donald Hebb postulated that assemblies of synchronously activated neurons are the elementary units of information processing in the brain. Despite being one of the most influential theories in neuroscience, Hebb's cell assembly hypothesis only started to become testable in the past two decades due to technological advances. However, while the technology for the simultaneous recording of large neuronal populations undergoes fast development, there is still a paucity of analytical methods that can properly detect and track the activity of cell assemblies. Here we describe a principal component-based method that is able to (1) identify all cell assemblies present in the neuronal population investigated, (2) determine the number of neurons involved in ensemble activity, (3) specify the precise identity of the neurons pertaining to each cell assembly, and (4) unravel the time course of the individual activity of multiple assemblies. Application of the method to multielectrode recordings of awake and behaving rats revealed that assemblies detected in the cerebral cortex and hippocampus typically contain overlapping neurons. The results indicate that the PCA method presented here is able to properly detect, track and specify neuronal assemblies, irrespective of overlapping membership.
doi_str_mv 10.1371/journal.pone.0020996
format Article
fullrecord <record><control><sourceid>gale_plos_</sourceid><recordid>TN_cdi_plos_journals_1304647246</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><galeid>A476888152</galeid><doaj_id>oai_doaj_org_article_c210ad22afcf4bdfa35ada7bf6d42598</doaj_id><sourcerecordid>A476888152</sourcerecordid><originalsourceid>FETCH-LOGICAL-c757t-94a13bebe6d9ce8382692840981a92e94bcdbca4db7e754672da8d66d451494b3</originalsourceid><addsrcrecordid>eNqNk1uL1DAUx4so7rr6DUQLguLDjLk1lxdhWbwMLC54e5NwmqQzGdqm27TifHvTne4yI_sgfUjJ-f3_5-TkJMueY7TEVOB32zD2LdTLLrRuiRBBSvEH2SlWlCw4QfThwf9J9iTGLUIFlZw_zk4I5koSJk-zX1_c2Ifkk0OMrinrXW7d4MzgQ5tDa3Pj6jpvUsT1ceO7PHbO-MobuCHKXd71vjW-Sw4mNFMx7ZCEUO-ij0-zRxXU0T2b17Psx8cP3y8-Ly6vPq0uzi8XRhRiWCgGmJaudNwq4ySVhCsiGVISgyJOsdLY0gCzpXCiYFwQC9JyblmBWYrSs-zl3rerQ9RzZ6LGFDHOBGE8Eas9YQNsdaq5gX6nA3h9sxH6tYZ-8KZ22hCMwBIClalYaSugBVgQZZXykULJ5PV-zjaWjbMmnbiH-sj0ONL6jV6H35piXCiBksGb2aAP16OLg258nBoNrQtj1FLQRCkyka_-Ie8_3EytIdXv2yqktGby1OdMcCklLkiilvdQ6bOu8SZdXOXT_pHg7ZEgMYP7M6xhjFGvvn39f_bq5zH7-oDdOKiHTQz1OE1UPAbZHjR9iLF31V2PMdLTI7jthp7mTs-PIMleHN7Pneh26ulfgtAD3g</addsrcrecordid><sourcetype>Open Website</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>1304647246</pqid></control><display><type>article</type><title>Neuronal assembly detection and cell membership specification by principal component analysis</title><source>MEDLINE</source><source>DOAJ Directory of Open Access Journals</source><source>Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals</source><source>Public Library of Science (PLoS)</source><source>PubMed Central</source><source>Free Full-Text Journals in Chemistry</source><creator>Lopes-dos-Santos, Vítor ; Conde-Ocazionez, Sergio ; Nicolelis, Miguel A L ; Ribeiro, Sidarta T ; Tort, Adriano B L</creator><contributor>Perc, Matjaz</contributor><creatorcontrib>Lopes-dos-Santos, Vítor ; Conde-Ocazionez, Sergio ; Nicolelis, Miguel A L ; Ribeiro, Sidarta T ; Tort, Adriano B L ; Perc, Matjaz</creatorcontrib><description>In 1949, Donald Hebb postulated that assemblies of synchronously activated neurons are the elementary units of information processing in the brain. Despite being one of the most influential theories in neuroscience, Hebb's cell assembly hypothesis only started to become testable in the past two decades due to technological advances. However, while the technology for the simultaneous recording of large neuronal populations undergoes fast development, there is still a paucity of analytical methods that can properly detect and track the activity of cell assemblies. Here we describe a principal component-based method that is able to (1) identify all cell assemblies present in the neuronal population investigated, (2) determine the number of neurons involved in ensemble activity, (3) specify the precise identity of the neurons pertaining to each cell assembly, and (4) unravel the time course of the individual activity of multiple assemblies. Application of the method to multielectrode recordings of awake and behaving rats revealed that assemblies detected in the cerebral cortex and hippocampus typically contain overlapping neurons. The results indicate that the PCA method presented here is able to properly detect, track and specify neuronal assemblies, irrespective of overlapping membership.</description><identifier>ISSN: 1932-6203</identifier><identifier>EISSN: 1932-6203</identifier><identifier>DOI: 10.1371/journal.pone.0020996</identifier><identifier>PMID: 21698248</identifier><language>eng</language><publisher>United States: Public Library of Science</publisher><subject>Algorithms ; Analysis ; Analytical methods ; Assemblies ; Assembly ; Biology ; Brain ; Cerebral cortex ; Data analysis ; Data processing ; Information processing ; Nervous system ; Neurons ; Neurons - cytology ; Neurosciences ; Principal Component Analysis ; Principal components analysis ; Rats ; Santos, Sergio ; Technology application ; Trends</subject><ispartof>PloS one, 2011-06, Vol.6 (6), p.e20996-e20996</ispartof><rights>COPYRIGHT 2011 Public Library of Science</rights><rights>2011 Lopes-dos-Santos et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License: https://creativecommons.org/licenses/by/4.0/ (the “License”), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.</rights><rights>Lopes-dos-Santos et al. 2011</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c757t-94a13bebe6d9ce8382692840981a92e94bcdbca4db7e754672da8d66d451494b3</citedby><cites>FETCH-LOGICAL-c757t-94a13bebe6d9ce8382692840981a92e94bcdbca4db7e754672da8d66d451494b3</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3115970/pdf/$$EPDF$$P50$$Gpubmedcentral$$Hfree_for_read</linktopdf><linktohtml>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3115970/$$EHTML$$P50$$Gpubmedcentral$$Hfree_for_read</linktohtml><link.rule.ids>230,314,723,776,780,860,881,2095,2914,23846,27903,27904,53770,53772,79347,79348</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/21698248$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><contributor>Perc, Matjaz</contributor><creatorcontrib>Lopes-dos-Santos, Vítor</creatorcontrib><creatorcontrib>Conde-Ocazionez, Sergio</creatorcontrib><creatorcontrib>Nicolelis, Miguel A L</creatorcontrib><creatorcontrib>Ribeiro, Sidarta T</creatorcontrib><creatorcontrib>Tort, Adriano B L</creatorcontrib><title>Neuronal assembly detection and cell membership specification by principal component analysis</title><title>PloS one</title><addtitle>PLoS One</addtitle><description>In 1949, Donald Hebb postulated that assemblies of synchronously activated neurons are the elementary units of information processing in the brain. Despite being one of the most influential theories in neuroscience, Hebb's cell assembly hypothesis only started to become testable in the past two decades due to technological advances. However, while the technology for the simultaneous recording of large neuronal populations undergoes fast development, there is still a paucity of analytical methods that can properly detect and track the activity of cell assemblies. Here we describe a principal component-based method that is able to (1) identify all cell assemblies present in the neuronal population investigated, (2) determine the number of neurons involved in ensemble activity, (3) specify the precise identity of the neurons pertaining to each cell assembly, and (4) unravel the time course of the individual activity of multiple assemblies. Application of the method to multielectrode recordings of awake and behaving rats revealed that assemblies detected in the cerebral cortex and hippocampus typically contain overlapping neurons. The results indicate that the PCA method presented here is able to properly detect, track and specify neuronal assemblies, irrespective of overlapping membership.</description><subject>Algorithms</subject><subject>Analysis</subject><subject>Analytical methods</subject><subject>Assemblies</subject><subject>Assembly</subject><subject>Biology</subject><subject>Brain</subject><subject>Cerebral cortex</subject><subject>Data analysis</subject><subject>Data processing</subject><subject>Information processing</subject><subject>Nervous system</subject><subject>Neurons</subject><subject>Neurons - cytology</subject><subject>Neurosciences</subject><subject>Principal Component Analysis</subject><subject>Principal components analysis</subject><subject>Rats</subject><subject>Santos, Sergio</subject><subject>Technology application</subject><subject>Trends</subject><issn>1932-6203</issn><issn>1932-6203</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2011</creationdate><recordtype>article</recordtype><sourceid>EIF</sourceid><sourceid>ABUWG</sourceid><sourceid>AFKRA</sourceid><sourceid>AZQEC</sourceid><sourceid>BENPR</sourceid><sourceid>CCPQU</sourceid><sourceid>DWQXO</sourceid><sourceid>GNUQQ</sourceid><sourceid>DOA</sourceid><recordid>eNqNk1uL1DAUx4so7rr6DUQLguLDjLk1lxdhWbwMLC54e5NwmqQzGdqm27TifHvTne4yI_sgfUjJ-f3_5-TkJMueY7TEVOB32zD2LdTLLrRuiRBBSvEH2SlWlCw4QfThwf9J9iTGLUIFlZw_zk4I5koSJk-zX1_c2Ifkk0OMrinrXW7d4MzgQ5tDa3Pj6jpvUsT1ceO7PHbO-MobuCHKXd71vjW-Sw4mNFMx7ZCEUO-ij0-zRxXU0T2b17Psx8cP3y8-Ly6vPq0uzi8XRhRiWCgGmJaudNwq4ySVhCsiGVISgyJOsdLY0gCzpXCiYFwQC9JyblmBWYrSs-zl3rerQ9RzZ6LGFDHOBGE8Eas9YQNsdaq5gX6nA3h9sxH6tYZ-8KZ22hCMwBIClalYaSugBVgQZZXykULJ5PV-zjaWjbMmnbiH-sj0ONL6jV6H35piXCiBksGb2aAP16OLg258nBoNrQtj1FLQRCkyka_-Ie8_3EytIdXv2yqktGby1OdMcCklLkiilvdQ6bOu8SZdXOXT_pHg7ZEgMYP7M6xhjFGvvn39f_bq5zH7-oDdOKiHTQz1OE1UPAbZHjR9iLF31V2PMdLTI7jthp7mTs-PIMleHN7Pneh26ulfgtAD3g</recordid><startdate>20110615</startdate><enddate>20110615</enddate><creator>Lopes-dos-Santos, Vítor</creator><creator>Conde-Ocazionez, Sergio</creator><creator>Nicolelis, Miguel A L</creator><creator>Ribeiro, Sidarta T</creator><creator>Tort, Adriano B L</creator><general>Public Library of Science</general><general>Public Library of Science (PLoS)</general><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>IOV</scope><scope>ISR</scope><scope>3V.</scope><scope>7QG</scope><scope>7QL</scope><scope>7QO</scope><scope>7RV</scope><scope>7SN</scope><scope>7SS</scope><scope>7T5</scope><scope>7TG</scope><scope>7TM</scope><scope>7U9</scope><scope>7X2</scope><scope>7X7</scope><scope>7XB</scope><scope>88E</scope><scope>8AO</scope><scope>8C1</scope><scope>8FD</scope><scope>8FE</scope><scope>8FG</scope><scope>8FH</scope><scope>8FI</scope><scope>8FJ</scope><scope>8FK</scope><scope>ABJCF</scope><scope>ABUWG</scope><scope>AEUYN</scope><scope>AFKRA</scope><scope>ARAPS</scope><scope>ATCPS</scope><scope>AZQEC</scope><scope>BBNVY</scope><scope>BENPR</scope><scope>BGLVJ</scope><scope>BHPHI</scope><scope>C1K</scope><scope>CCPQU</scope><scope>D1I</scope><scope>DWQXO</scope><scope>FR3</scope><scope>FYUFA</scope><scope>GHDGH</scope><scope>GNUQQ</scope><scope>H94</scope><scope>HCIFZ</scope><scope>K9.</scope><scope>KB.</scope><scope>KB0</scope><scope>KL.</scope><scope>L6V</scope><scope>LK8</scope><scope>M0K</scope><scope>M0S</scope><scope>M1P</scope><scope>M7N</scope><scope>M7P</scope><scope>M7S</scope><scope>NAPCQ</scope><scope>P5Z</scope><scope>P62</scope><scope>P64</scope><scope>PATMY</scope><scope>PDBOC</scope><scope>PIMPY</scope><scope>PQEST</scope><scope>PQQKQ</scope><scope>PQUKI</scope><scope>PRINS</scope><scope>PTHSS</scope><scope>PYCSY</scope><scope>RC3</scope><scope>7X8</scope><scope>5PM</scope><scope>DOA</scope></search><sort><creationdate>20110615</creationdate><title>Neuronal assembly detection and cell membership specification by principal component analysis</title><author>Lopes-dos-Santos, Vítor ; Conde-Ocazionez, Sergio ; Nicolelis, Miguel A L ; Ribeiro, Sidarta T ; Tort, Adriano B L</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c757t-94a13bebe6d9ce8382692840981a92e94bcdbca4db7e754672da8d66d451494b3</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2011</creationdate><topic>Algorithms</topic><topic>Analysis</topic><topic>Analytical methods</topic><topic>Assemblies</topic><topic>Assembly</topic><topic>Biology</topic><topic>Brain</topic><topic>Cerebral cortex</topic><topic>Data analysis</topic><topic>Data processing</topic><topic>Information processing</topic><topic>Nervous system</topic><topic>Neurons</topic><topic>Neurons - cytology</topic><topic>Neurosciences</topic><topic>Principal Component Analysis</topic><topic>Principal components analysis</topic><topic>Rats</topic><topic>Santos, Sergio</topic><topic>Technology application</topic><topic>Trends</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Lopes-dos-Santos, Vítor</creatorcontrib><creatorcontrib>Conde-Ocazionez, Sergio</creatorcontrib><creatorcontrib>Nicolelis, Miguel A L</creatorcontrib><creatorcontrib>Ribeiro, Sidarta T</creatorcontrib><creatorcontrib>Tort, Adriano B L</creatorcontrib><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>Gale In Context: Opposing Viewpoints</collection><collection>Gale In Context: Science</collection><collection>ProQuest Central (Corporate)</collection><collection>Animal Behavior Abstracts</collection><collection>Bacteriology Abstracts (Microbiology B)</collection><collection>Biotechnology Research Abstracts</collection><collection>Nursing &amp; Allied Health Database</collection><collection>Ecology Abstracts</collection><collection>Entomology Abstracts (Full archive)</collection><collection>Immunology Abstracts</collection><collection>Meteorological &amp; Geoastrophysical Abstracts</collection><collection>Nucleic Acids Abstracts</collection><collection>Virology and AIDS Abstracts</collection><collection>Agricultural Science Collection</collection><collection>Health &amp; Medical Collection</collection><collection>ProQuest Central (purchase pre-March 2016)</collection><collection>Medical Database (Alumni Edition)</collection><collection>ProQuest Pharma Collection</collection><collection>ProQuest Public Health Database</collection><collection>Technology Research Database</collection><collection>ProQuest SciTech Collection</collection><collection>ProQuest Technology Collection</collection><collection>ProQuest Natural Science Collection</collection><collection>Hospital Premium Collection</collection><collection>Hospital Premium Collection (Alumni Edition)</collection><collection>ProQuest Central (Alumni) (purchase pre-March 2016)</collection><collection>Materials Science &amp; Engineering Collection</collection><collection>ProQuest Central (Alumni Edition)</collection><collection>ProQuest One Sustainability</collection><collection>ProQuest Central UK/Ireland</collection><collection>Advanced Technologies &amp; Aerospace Collection</collection><collection>Agricultural &amp; Environmental Science Collection</collection><collection>ProQuest Central Essentials</collection><collection>Biological Science Collection</collection><collection>ProQuest Central</collection><collection>Technology Collection</collection><collection>Natural Science Collection</collection><collection>Environmental Sciences and Pollution Management</collection><collection>ProQuest One Community College</collection><collection>ProQuest Materials Science Collection</collection><collection>ProQuest Central Korea</collection><collection>Engineering Research Database</collection><collection>Health Research Premium Collection</collection><collection>Health Research Premium Collection (Alumni)</collection><collection>ProQuest Central Student</collection><collection>AIDS and Cancer Research Abstracts</collection><collection>SciTech Premium Collection</collection><collection>ProQuest Health &amp; Medical Complete (Alumni)</collection><collection>Materials Science Database</collection><collection>Nursing &amp; Allied Health Database (Alumni Edition)</collection><collection>Meteorological &amp; Geoastrophysical Abstracts - Academic</collection><collection>ProQuest Engineering Collection</collection><collection>ProQuest Biological Science Collection</collection><collection>Agricultural Science Database</collection><collection>Health &amp; Medical Collection (Alumni Edition)</collection><collection>Medical Database</collection><collection>Algology Mycology and Protozoology Abstracts (Microbiology C)</collection><collection>Biological Science Database</collection><collection>Engineering Database</collection><collection>Nursing &amp; Allied Health Premium</collection><collection>Advanced Technologies &amp; Aerospace Database</collection><collection>ProQuest Advanced Technologies &amp; Aerospace Collection</collection><collection>Biotechnology and BioEngineering Abstracts</collection><collection>Environmental Science Database</collection><collection>Materials Science Collection</collection><collection>Publicly Available Content Database</collection><collection>ProQuest One Academic Eastern Edition (DO NOT USE)</collection><collection>ProQuest One Academic</collection><collection>ProQuest One Academic UKI Edition</collection><collection>ProQuest Central China</collection><collection>Engineering Collection</collection><collection>Environmental Science Collection</collection><collection>Genetics Abstracts</collection><collection>MEDLINE - Academic</collection><collection>PubMed Central (Full Participant titles)</collection><collection>DOAJ Directory of Open Access Journals</collection><jtitle>PloS one</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Lopes-dos-Santos, Vítor</au><au>Conde-Ocazionez, Sergio</au><au>Nicolelis, Miguel A L</au><au>Ribeiro, Sidarta T</au><au>Tort, Adriano B L</au><au>Perc, Matjaz</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Neuronal assembly detection and cell membership specification by principal component analysis</atitle><jtitle>PloS one</jtitle><addtitle>PLoS One</addtitle><date>2011-06-15</date><risdate>2011</risdate><volume>6</volume><issue>6</issue><spage>e20996</spage><epage>e20996</epage><pages>e20996-e20996</pages><issn>1932-6203</issn><eissn>1932-6203</eissn><abstract>In 1949, Donald Hebb postulated that assemblies of synchronously activated neurons are the elementary units of information processing in the brain. Despite being one of the most influential theories in neuroscience, Hebb's cell assembly hypothesis only started to become testable in the past two decades due to technological advances. However, while the technology for the simultaneous recording of large neuronal populations undergoes fast development, there is still a paucity of analytical methods that can properly detect and track the activity of cell assemblies. Here we describe a principal component-based method that is able to (1) identify all cell assemblies present in the neuronal population investigated, (2) determine the number of neurons involved in ensemble activity, (3) specify the precise identity of the neurons pertaining to each cell assembly, and (4) unravel the time course of the individual activity of multiple assemblies. Application of the method to multielectrode recordings of awake and behaving rats revealed that assemblies detected in the cerebral cortex and hippocampus typically contain overlapping neurons. The results indicate that the PCA method presented here is able to properly detect, track and specify neuronal assemblies, irrespective of overlapping membership.</abstract><cop>United States</cop><pub>Public Library of Science</pub><pmid>21698248</pmid><doi>10.1371/journal.pone.0020996</doi><tpages>e20996</tpages><oa>free_for_read</oa></addata></record>
fulltext fulltext
identifier ISSN: 1932-6203
ispartof PloS one, 2011-06, Vol.6 (6), p.e20996-e20996
issn 1932-6203
1932-6203
language eng
recordid cdi_plos_journals_1304647246
source MEDLINE; DOAJ Directory of Open Access Journals; Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals; Public Library of Science (PLoS); PubMed Central; Free Full-Text Journals in Chemistry
subjects Algorithms
Analysis
Analytical methods
Assemblies
Assembly
Biology
Brain
Cerebral cortex
Data analysis
Data processing
Information processing
Nervous system
Neurons
Neurons - cytology
Neurosciences
Principal Component Analysis
Principal components analysis
Rats
Santos, Sergio
Technology application
Trends
title Neuronal assembly detection and cell membership specification by principal component analysis
url https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-21T11%3A57%3A26IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-gale_plos_&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Neuronal%20assembly%20detection%20and%20cell%20membership%20specification%20by%20principal%20component%20analysis&rft.jtitle=PloS%20one&rft.au=Lopes-dos-Santos,%20V%C3%ADtor&rft.date=2011-06-15&rft.volume=6&rft.issue=6&rft.spage=e20996&rft.epage=e20996&rft.pages=e20996-e20996&rft.issn=1932-6203&rft.eissn=1932-6203&rft_id=info:doi/10.1371/journal.pone.0020996&rft_dat=%3Cgale_plos_%3EA476888152%3C/gale_plos_%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_pqid=1304647246&rft_id=info:pmid/21698248&rft_galeid=A476888152&rft_doaj_id=oai_doaj_org_article_c210ad22afcf4bdfa35ada7bf6d42598&rfr_iscdi=true