認(rèn)知心理學(xué)課件-何生

NeuralCorrelatesofVisualAwarenessShengHe

UniversityofMinnesota1V1

LGN2PhysicalstimuliPerceptualexperienceSamestimuliDifferentperceptsDifferentstimuliSamepercept3PhysicalstimuliPerceptualexperienceLocalizedneuralactivity??AreasinwhichactivitieschangewithstimuliarenotgoodcandidatesofNCC.differentsame4PhysicalstimuliPerceptualexperienceLocalizedneuralactivitysamedifferent??movingAreasinwhichactivitieschangewithperceptionaregoodcandidatesofNCC.static5PhysicalstimuliPerceptualexperienceLocalizedneuralactivity??orrivalryAreasinwhichactivitieschangewithperceptionaregoodcandidatesofNCC.samedifferentor6PartI:adaptationtoinvisiblestimuli (withDonMacLeod)PartII:motionaftereffect (withEricCohen,XiaopingHu)PartIII:binocularrivalry --parallelpathwaystovisualawareness (withTomCarlson)7PhysicalstimuliPerceptualexperienceLocalizedneuralactivitydifferentsameCanneuronsinareaXtellthedifference?AreasinwhichactivitieschangewithstimuliarenotgoodcandidatesofNCC.PartI:adaptationtoinvisiblestimuli8PhysicalstimuliPerceptualexperienceLocalizedneuralactivity

V1??cancauseorientation-selectiveadaptation?9Spatialfrequency(cycles/degree)SensitivityResolutionlimit:50cpdUnresolvable10Orientation-SelectiveAdaptationAdaptTestSameOrientationHardtosee!NeedhighcontrastOrthogonalOrientationEasytosee!Needlowcontrast11Tilt-aftereffect1213V1isthefirststageinthevisualsystemwhereorientationinformationisextracted: orientation-selectiveadaptationisonly possibleatorafterV1. Ifwefindevidencefororientation- selectiveadaptation,thenitimplies thattheorientationinformationhasat leastreachedV1.14InvisibleverticalgratingAdaptTestSameOrientationNeedhighercontrastOrthogonalOrientationNeedlowercontrastResult15HeandMacLeod,Nature20011617Orientation-selectiveadaptationfromaninvisiblespatialpattern: invisibletotheobserverbutvisibleatV1. Thereisintra-corticallossofspatial information. V1activityisnotsufficientforvisual awareness.18PartISummaryFinespatialpatternscanbe“visible”atV1butinvisibletotheobserver.V1activityisnotalwayscorrelateddirectlywithvisualawareness.19Caveats:1.Maybenosingleareawillbe“sufficient”forvisualawareness.ThisapproachmayleadtotherejectionofthewholebrainasNCC.2.IndividualcorticalareamaynotbetherightunittoconsiderfortheNCC.Differenttypesofneuronsexistineacharea.20PhysicalstimuliPerceptualexperienceLocalizedneuralactivitysamedifferent??movingAreasinwhichactivitieschangewithperceptionaregoodcandidatesofNCC.staticPartII:motionaftereffect21motionaftereffectdemo22MT/V5activity:motion-stationaryMT+23PhysicalstimuliPerceptualExperience(afteradaptation)Localizedneuralactivity

MT??SeeingMotionaftereffect24illusorymotionstationaryAdapt(moving)fixationPerceptionTest(stationary)Motionaftereffect:2526He,Cohen,&Hu,CurrentBiology,199827PartIISummaryMTactivityiscloselycorrelatedwiththeperceptionofmotionaftereffect.yetanotherexpfromus(notreportedhere)showedthatMTactivityaloneisnotsufficientfortheperceptionofmotion.28PhysicalstimuliPerceptualexperienceLocalizedneuralactivityGratingvs.UniformfieldStationaryvs.StationaryUniformfieldvs.UniformfieldMovingvs.StationarySummaryofpartIandII29PhysicalstimuliPerceptualexperienceLocalizedneuralactivity??orrivalryAreasinwhichactivitieschangewithperceptionaregoodcandidatesofNCC.PartIII:parallelpathwaystovisualawareness30stereoscope31BinocularRivalryPercept:alternatingviewsovertimeLefteyeRighteyeStimuli(e.g.):time32eyeLGNV1extrastriatefrontal???Ansimplisticview:33Notalldichopticdifferencescauserivalry:O'Shea&Blake(1986).Dichoptictemporalfrequencydifferencesdonotleadtobinocularrivalry.Perception&Psychophysics,v39(n1):59-63

34BinocularVisualBeatsIntegrationofhightemporalfrequencyluminanceinformationbetweentwoeyesLeftEye(28Hz)RightEye(30Hz)Binocularpercept(2Hzbeat)35Binocularrivalry:inter-ocularsuppressionBinocularbeats:inter-ocularsummationCantheybeperceivedsimultaneously?36StimulusLefteyeRighteyeDifferencesinshapeandcolorinthetwoeyescanpotentiallyleadtobinocularrivalry.Twoeyes’flickerswithslightdifferenttemporal

frequencycanpotentiallyleadtobinocularbeats.37PossiblePercepts:Beats:Rivalry:orOr??38ResultsObserversperceivebothrivalryandbeatsRivalry

&

Beats39eyeLGNV1extrastriatefrontal???40MagnoParvo41Magno-ParvoProposalStimulithattendtointegrateinsteadofrival:flicker(O’Shea&Blake,1986) binocularbeats(Carlson&He,2000)

stereopsis(Wolfe,1986)

lowcontraststimuli(Liu,Tyler,&Schor,1992)

inter-ocularintegrationofmotion(shortduration)(Andrews&Blakemore,1999)

(Carney,

Shadlen,&Switkes,1987)FastflickerandmotionaremainlyprocessedintheMagno-Pathway42retinaLGNV1extrastriatefrontalventraldorsalparietaltemporalrivalryfusion43

Rivalryasafunctionofmotionspeed:M-biasedcondition:fast,20HzP-biasedcondition:slow,2HzContrastsat10XmotiondetectionthresholdSubjectsrecordedpercept:

Motionrivalryorcounter-phaseflicker?44ResultsParvo-biasedcondition:71%Rivalry,29%Summation/MixingMagno-biasedcondition: 28%Rivalry,72%Summation/Mixingslowmotion(2Hz)fastmotion(20Hz)%timerivalry105090Subj.1Subj.2Carlson&H