fMRIActivationinaVisual-PerceptionTaskNetworkof：fMRI激活在视觉感知任务网络

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1、fMRIActivationinaVisual-PerceptionTask:NetworkofAreasDetectedUsingtheGeneralLinearModelandIndependentComponentsAnalysisCalhoun,Adali,McGinty,Pekar,Watson,&Pearlson(2001).GenevièveDesmarais-November5,2002MVPT-RMotor-freeVisualPerceptionTask(Revised)Probes:spatialrelationships

2、visualdiscriminationfigure-groundperceptionvisualclosureetc...BasicParadigmParticipants2females,8malesmeanage27screenedwithphysicalandneurologicalexamnoAxis1disorders(clinical)goodvisualacuitywithoutcorrectionImagingParametersAnatomicScanT-1weightedTR=500msecTE=30msecsliceth

3、ickness=5mmgap=0.5mm18slicesthroughentirebrainFunctionalScansingle-shotecho-planarTR=1sTE=39msec5min=300scans10dummyscansatbeginningDataAnalysis-Preprocessing(fudging?)CorrectedfortimingdifferencesMotioncorrectedSpatiallysmoothedNormalizedtoTalairachspaceDataAnalysisGenera

4、lLinearModel1.Fixed-effectgroupanalysisstimulusfunctiontimeswhenfigureswerepresentedtotheparticipantsFilters:High-passLowpasstrendsverifiedineachindividualdataset2.RandomeffectanalysisonindividualdataDataAnalysisIndependentComponentAnalysisDecomposesdataintosignalsthatarema

5、ximallyindependentindividualpreprocesseddataarrangedinto2Dmatrixofspaceandtime20componentsestimated,groupedinto:motor,visual,cerebellar,frontoparietal,orbitofrontal,andbasalgangliaDataAnalysisIndependentComponentAnalysisComponentsnormalizedComponentswithineachareaaveragedac

6、rossparticipantsEachgroupimageconvertedtoZscoresthreshold=2.5Results85%averagecorrectresponserange67-100(…)IncorrectandcorrectresponsesgroupedtogetherActivationGLManalysis*visualareas*visualassociation*frontaleyefields*dorsolateralprefrontal*supplementalmotor*nopositivepari

7、etal*extensivecerebellarActivationICAanalysis*colours=diffcomponent*mostlysameregions*superiorparietalandprefrontalinsameasFEFDiscussionExpectedactivationin:largenetworkofareasinvolvedinvisualandspatialperceptionallprimaryvisualareasandmanyvisualassociationareasEvent-averag

8、edtimecoursesParietalregionsDecreasingsignalfollowingfiguralpresentationatt