oscillations脑震荡课件

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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