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ID:20639988
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时间:2018-10-14
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1、Neuromodulationsignal-to-noiseswitchingburst/singlespikeoscillationsNeuromodulatorsalterintrinsicpropertiesofnetworksMarderandThilumalai,2002BrainOscillationsOscillationsemergefromtheinteractionbetweenintrinsiccellularpropertiesandcircuitproperties.i
2、ndividualoscillatoryneuronsindividualnon-oscillatingneuronsthatarehookedupinaspecificnetworkthatproducesoscillation.Inmanysystemselectricalcouplingbygapjunctionstendtoproduceoscillatorysynchronization.CharacteristicsofMammalianOscillationsPhylogeneti
3、cpreservationinmammals.Inmammals,frequenciesclusteraroundspecificpeaks-unlikevertebrateswhoshowmuchmoredistributedfrequencies.Powerdensityoftheseoscillationsisinverselyproportionaltofrequency(1/f)This(1/f)relationshipimpliesthatperturbationsoccurring
4、atslowfrequenciescauseacascadeofenergydissipationathigherfrequencies(i.e.,slowoscillationsmodulatefasterlocalevents).TypesofOscillationsBrainnetworksoscillateandtheiroscillationsarebehaviordependent.Oscillationsrangefrom0.05Hzto500Hzsotherangeismanyo
5、rdersofmagnitude.Delta1-4HzTheta4-8HzAlpha8-12HzBeta13-20HzRoleofThalamocorticalLoopsManyoftherhythmicoscillationsproducedarisefromthalamocorticalre-entrantinteractionsandpacemakercellsthatcomprisethalamicnuclei.VentralPMC/PosteriorIFGSensorimotorcor
6、texRostralIPLHumanPF/PFGPosteriorSTSVisualinformationexternalcuesThalamusTheRoleofThalamocorticalLoopsSynchronizationofInputsAtleastthreetypesofsynchronieshavetheirelectrogenesisincortex.1. Thosecreatedlocallybetweenneighboringcolumns,whichproducehi
7、ghfrequencycomponentsabove30Hz(gammarhythms).Intermediateor“regional”oscillationsbetweencorticalcolumnsseparatedbyseveralcentimeters,whichproduceintermediatefrequencycomponents(highalpha/mu:>10Hz;andbeta:12-20Hz).Globalsynchroniesbetweencorticalregio
8、nsthataresignificantlyfarapart,suchasfrontalandparietaloroccipitalandfrontalregions.Thesearerelatedtoslowfrequencycomponents-delta(1-4Hz),theta(4-8Hz),andlowalpha/mu(8-10Hz).LocalandGlobalNetworksChoe,Y.IEEETrans.NeuralNet.,2003,15(5):1480-1485Localn
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