Analysis of a phase synchronized functional network based on the rhythm of brain activities

(整期优先)网络出版时间:2011-03-13
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Rhythmofbrainactivitiesrepresentsoscillationsofpostsynapticpotentialsinneocortex,thereforeitcanserveasanindicatorofthebrainactivitystate.Inordertochecktheconnectivityofbrainrhythm,thispaperdevelopsanewmethodofconstructingfunctionalnetworkbasedonphasesynchronization.Electroencephalogram(EEG)datawerecollectedwhilesubjectslookingatagreencrossintwostates,performinganattentiontaskandrelaxingwitheyes-open.TheEEGfromthesetwostateswasfilteredbythreeband-passfilterstoobtainsignalsoftheta(4-7Hz),alpha(8-13Hz)andbeta(14-30Hz)bands.Meanresultantlengthwasusedtoestimatestrengthofphasesynchronizationinthreebandstoconstructnetworksofbothstates,andmeandegreeKandclustercoefficientCofnetworkswerecalculatedasafunctionofthreshold.Theresultshowshigherclustercoefficientintheattentionstatethanintheeyes-openstateinallthreebands,suggestingthatclustercoefficientreflectsbrainstate.Inaddition,anobviousfronto-parietalnetworkisfoundintheattentionstate,whichisawell-knownattentionnetwork.Theseresultsindicatethatattentionmodulatesthefronto-parietalconnectivityindifferentmodesascomparedwiththeeyes-openstate.Takentogetherthismethodisanobjectiveandimportanttooltostudythepropertiesofneuralnetworksofbrainrhythm.