Helmholtz Retreat 2016 · Proceedings of the 8th Helmholtz Retreat 5 Program Locations: All...

Proceedings of the 8th Helmholtz Retreat

Jun 29th - July 1stVenue: Hotel Jan van Scorel,

Schoorl, The Netherlands

Helmholtz Retreat 2016

Proceedingsofthe8thHelmholtzRetreat

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HelmholtzCommitteeOfficemanagementMrs.EvelineHeerens, UtrechtUniversityOrginizersRetreatDr.AnoukKeizer, UtrechtUniversityDr.SjoerdStuit, UtrechtUniversityProf.Dr.LeonKenemans, UtrechtUniversityProf.Dr.ChrisDijkerman, UtrechtUniversityPaulZerr(HelmholtzPhDcouncil), UtrechtUniversity


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TableofContentsWelcome byChrisDijkerman Page4Program CompleteSchedule Page5KeynoteJohanWagemans Abstract&AboutJohan Page6KeynoteKarinRoelofs Abstract&AboutKarin Page7SessionDetails WednesdaySessions1-2 Page8ThursdaySessions3-5 Page9FrydaySessions6-7 Page10PostersandDemos Page11SpeakerAbstracts Page12


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WelcomeThis year, the Helmholtz retreat will beheld for the eighth time. Indeed, it hasbecome a well-established tradition.Althoughlocationandparticipatinggroupshavechangedovertheyears,theformatofthe retreat has essentially stayed thesame. It involves a mixture of scientificpresentations in various sessions ondifferenttopicsbyPhDstudents,combinedwith lectures by (inter)national guestspeakers and sufficient time for informalchatsaboutresearchoranyothertopic,awalk on the beach etc. This persistencewithrespecttotheformatisnotsurprisingasitishighlystimulatingandwell-regardedbyattendees.

Prof.Dr.ChrisDijkerman

SinceourlastHelmholtzretreatinJune2014afewsignificanteventshavetakenplacewithintheresearchschool.ColleaguesfromLinguisticdepartmentinUtrechthavejoinedandtheHelmholtzSchoolhas(re)gainedaccreditationasanationalresearchschoolfromtheKNAW.AtthesametimeHelmholtzactivitiescontinuethewaytheyhavedoneformanyyears.Forexample,theHelmholtzlectureserieseachyearcontainsrenownedinternationalspeakersand Helmholtz PhD days are organised every 6 months. No doubt the highlight of theHelmholtzactivitiescalendarremainstheHelmholtzretreat.The program of this year’s retreat comprises presentations from established Helmholtzgroups(e.g.ErasmusUniversity,theFreeUniversityandUtrechtUniversity)aswellasfromgroups(healthandsocialpsychology,linguistics)thathavejoinedmorerecently.Iwouldliketo thankSjoerdStuitandAnoukKeizer forall theeffort thathaveput intoorganizing theretreatandIlookforwardtoyetanotherhighlystimulatingretreat.ChrisDijkermanChairmanoftheboardoftheHelmholtzResearchSchool


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Program

Locations:AllsessionswillintheTuinzaal.Duringthebreaks,coffeewillbeavailableinatthebaror,iftheweatherpermits,inthegarden.Breakfast,lunchanddinerwillbeintherestaurant'KanunniK'.TheBBQwillbeattheterraceandthegarden.WednesdayJune299.30-10.00 ArrivalPhDstudents10.00-13.00 PhDonlysessionWorkshoponpresentingDiscussionHHherald12.00-13.00 Arrivalotherguests13.00-14.15 Lunch14.15-14.30 OpeningbyLeonKenemans14.30-15.30 Session1:Bodyperception&actionI15.30-15.45 Break15.45-16.45 Session2:Bodyperception&actionII16.45-17:45 Break(withsnacks!)17.45-19.00 KeynoteJohanWagemans19.00-21.00 DinerThursdayJune307.30-9.00 Breakfast9.15-10.35 Session3:Eyemovements10.35-10.50 Break10.50-12.10 Session4:Affectiveprocesses12.10-12.30 Break12.30-14.00 Lunch14.00-15.20 Session5:Languageanddevelopment15.20-16:30 Timeforsomefreshair!16.30-17.30 Businessmeeting17.30-17.45 Break(withsnacks!)17.45-19.00 KeynoteKarinRoelofs19.00-21.00 BBQdinerFridayJuly17.30-9.00 Breakfast9.15-10.35 Session6:Socialandselfregulation10.35-12.00 Postersanddemo’s(andcoffee)12.00-13.15 Lunch13.15-14.50 Session7:Visualattention14.35-14.45 Closing


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KeynoteJohanWagemansWednesdayJune2917.45-19.00,KeynoteProf.Dr.JohanWagemansLaboratoryofExperimentalPsychology,UniversityofLeuven,Leuven,Belgium

Onvisionandart,gapsandbridges,thepainsandjoysof

collaborationswithartists,andmoreMore and more vision scientists areinterestedinstudyingvisualperceptionofart. Often this comes down to runningstandard psychophysical paradigms onricherstimuli.Sometimesonegoesas faras asking about preference and/orappreciation,inanattempttorelatevisualprocessing of art stimuli to aestheticresponses. Very rarely one includes realart, real artists, and real aestheticexperiencesintotheactualresearch.Thereareverygood reasons for this:One losesthefirmgroundofthewell-controlledlabexperiment and moves into the slipperyterrain of complex personal relationshipsandsubjectivefeelings.

Inthislecture,Iwillpresentanoverviewofourworkontheedgesbetweenvisualscienceofart, empirical aesthetics, and psychology of art. By doing this, I will illustrate some gapsbetweenthesedifferentworlds,andhowtobridgethem.Insomeoftheexamplestudies,thefocus isonvision, inothersonart,andinafewthetwoareinbalance. IwillalsoaddmypersonalreflectionsonwhatIhavelearnedfrommycollaborationswithartists,andwhatittakestomakeitwork.Iwillendwithsomesketchesofcurrentandfutureprojects.AboutJohan:Johan’smain interest is in perceptual organization (e.g., grouping, figure-ground, texture,depth,shape,objects).Specifically,hewantstocontributetounderstandingwhythingslookastheydo.Todoso,hecombinesphenomenological,psychophysical,computational,neural,ecologicalapproaches.


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KeynoteKarinRoelofsThursdayJune3017.45-19.00KeynoteProf.dr.KarinRoelofsDondersInstituteforBrainCognitionandBehavior&BehaviouralScienceInstitute,RadboudUniversity,Nijmegen,TheNetherlands

Neuro-endocrinecontrolmechanismsinsocialmotivationalaction

Functioning in social contexts requiresadequatecontroloversocialmotivationalactions. I will present a series of studiessuggesting that down-regulation ofamygdala activity by the anterior PFC isinvolved when people need to overridetheir automatic approach-avoidanceaction tendencies. I will show that thefunctioning of this neural circuitry issensitive to individual differences inemotional states (anxietyandaggression)andassociatedsteroidhormones(cortisolandtestosterone,respectively).

In addition, I will discuss recent direct manipulations of this neural circuitry by steroidhormoneadministrationandbrainstimulation(TMS).Ourresultssuggestthattheabilitytocontrolautomaticapproach-avoidanceactionsbythiscircuitryiscentralinexplaininghumanemotional responses and may constitute an important factor in explaining anxious andaggressivesymptomatology.AboutKarin:Karin's main interest is in the psychological and neuroendocrine mechanisms underlyingsocial-motivationalbehaviorinhealthyindividualsandthevariousformsofpsychopathologywheresocial-motivationalbehaviorisdisregulated.Sheaimstoincreaseinsightinaffectivedisordersandpromises toadvanceearlydetectionof symptomsand their treatment.Shestudies hormone-brain interactions in stress-related disorders (social phobia and PTSD),psychopathy and somatoform disorders (conversion and somatisation), using variousneurosciencetechniques:fMRI,EEG,andTMS.


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SessionDetails

WednesdayJune29

14.30-15.30 Session1:Bodyperception&actionI Moderator:AstridKappers 14.30-14.50ManasaKandula Therelativecontributionsofvisualandtactilestimulitothemultisensoryresponsein theperipersonalspace 14.50-15.10PeterHolland Aneuroanatomicallygroundedoptimalcontrolmodelofthecompensatoryeye movementsystem 15.10-15.30IreneKuling Sensorymatchingerrors

15.45-16.45 Session2:Bodyperception&actionII Moderator:JeroenSmeets 15.45-16.05MyrthePlaisier Timingofsizeandweightinthesize-weightillusion 16:05-16:25KaylaStone Measuringbodyrepresentationinthelowerlimbs 16:25-16:45ThomasHulst NoeffectsofcerebellarandM1transcranialdirectcurrentstimulationduring reachadaptationincerebellarpatients


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ThursdayJune30

9.15-10.35 Session3:Eyemovements Moderator:StefanvanderStigchel 9.15- 9.35JasperFabius Spatiotopicupdatingfacilitatespostsaccadicperception 9.35- 9.55PaulZerr Remappinghigh-capacity,pre-attentivevisual-spatialworkingmemory 9.55- 10.15MartijnSchut Usingvisuallyguidedcorrectivesaccadestoinvestigatetranssaccadicmemory 10.15-10.35JessicaHeeman Expresssaccades

10.50-12.10 Session4:Affectiveprocesses Moderator:JokeBaas 10.50- 11.10TabithaIseger TheDLPFC-sgACCnetwork:Gettingattheheartofit 11.10- 11.30SuryaGayet Visualinputsignalingthreatgainspreferentialaccesstoawareness 11.30- 11.50FebeEck-vanderFlier tobeannounced 11.50- 12.10IrisSchut Anticipatingrewardandprobability

14.00-15.20 Session5:Languageanddevelopment Moderator:JohanBolhuis 14.00- 14.20HannahDeMulder Figuring out what they feel: The role of narrative fiction in understanding others’ mentalstates 14.20- 14.40RiannevanRooijen Beneficialeffectsofthemother’svoiceonnovelwordlearningininfants 14.40- 15.00CarolineJunge Speakerfamiliarityaidsbothnovelwordencodingandmapping:ERPevidence 15.00- 15.20SitaterHaar Causalmechanisms in birdsong learning as amodel for human speech acquisition (VENIproposal)


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FridayJuly1

9.15-10.35 Session6:Socialandselfregulation Moderator:HenkAarts 9.15- 9.35AnoukvdWeiden Measuringautomaticassociationsinlongitudinaldesigns-Doesthelexicaldecision taskstandthetestoftime? 9.35- 9.55SamanthaAntush TheInfluenceofRewardingActionsonIntentionalBinding 9.55- 10.15JasperdeGroot LearningtoUnderstandHumanOlfactoryCommunication 10.15- 10.35IsabelMeier Naltrexoneincreasesnegatively-valencedmimicryinresponsetohappyfacial expressions

13.15-14.50 Session7:Visualattention Moderator:BasRokers 13.15- 13.35BarrieKlein Spatialattentionmodulatesrepresentationsofvisualspaceinhumans 13.35-13.55WietskeZuiderbaan Changeblindness:theroleoflow-levelandhigh-levelimagerepresentations 13.55- 14.15MaartjedeJong Intracranialrecordingsofoccipitalcortexresponsestoillusoryvisualevents 14.15- 14.35JimMaarseveen Spatialselectivityofthedurationafter-effect


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Posters&Demos

BasRokers,UniversityofWisconsin-Madison,USA Poster:TheneuralbasisofstereomotionscotomasJuttadeJong,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht Poster:Handpositionmodulatesvisually-drivenfMRIresponsesinpremotorareas Demo:VirtualrealitybodyswapillusionPaulZerr,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht Poster:Errorcorrectioninrandomvectordoublestepsaccades:withandwithoutglobal saccadeadaptationChristinadelaMalla,VrijeUniversiteit,HumanMovementSciences,Amsterdam Poster:Anotherreasonforfollowinganobjectwithone’seyesifoneintendstointerceptitMarijnStruiksma,UniversiteitUtrecht,UtrechtInstituteofLinguisticsOTS,Utrecht Poster:fEMGtijdenshetlezenvannarratieven Demo:fEMGandnarrativesEliBrenner,VrijeUniversiteit,HumanMovementSciences,Amsterdam Poster:AboutmeasuringreactiontimesKatinkavanderKooij,VrijeUniversiteit,HumanMovementSciences,Amsterdam Poster:tobeannounced Demo:OculusandKinectMyrthePlaisier,VrijeUniversiteit,HumanMovementSciences,Amsterdam Demo:SizeWeightIllusionMirandaSmit,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht Poster:Aclinicalcase:Bilateralownershipproblemsafterrightparietallesion Demo:RubberHandIllusionIreneKuling,VrijeUniversiteit,HumanMovementSciences,Amsterdam Demo:Aninconsistencybetweendifferentwaysofmatchingseenandfeltpositions


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SpeakerAbstracts

ManassaKandula,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Therelativecontributionsofvisualandtactilestimulitothemultisensoryresponseintheperipersonalspace

Thespacecloselysurroundingthebody,ortheperipersonalspace, isrepresentedbyanetworkofmultisensoryareasinthefrontalparietalcorticesofthebrain,thatrespondtovisual,auditoryandtactile stimuli. These neurons are found to be body-part centred, thereby responding tovisual/auditorystimuliaroundthebody-partevenasitmoves.Thevisual/auditoryreceptivefieldsofthese neurons are also found to extend several centimetres in space, surrounding the body part.Althoughtheseneuronsaremultisensoryinnature,itisunclearastowhethertheyaresummativeinnature,orselectivelyrespondtooneofthethreemodalitystimuliwhenpresentedwithboth.Inthefollowing human behavioural study, we use a visual-tactile redundant target effect paradigm, toinvestigatetherelativecontributionsofeithermodalitytothecombinedmultisensoryoutcome.Asstimuli,weuseapproachingvisualdots,thattheaforementionedmultisensoryareasareespeciallysensitive to, and short duration vibro-tactile stimuli. In order to ascertain that the multisensoryoutcomeisindeedaresultofperipersonalspacemodulation,wepresentthesevisualstimuliatseveraldepthsfromthesubject.Thepreliminaryresultsofthisstudywillbepresented.

PeterHolland,ErasmusMC,ErasmusUniversiteit,Rotterdam

Aneuroanatomicallygroundedoptimalcontrolmodelofthecompensatoryeyemovementsystem

Compensatoryeyemovementisageneraltermforseveralreflexeswhosegoalistomaintainastableimageontheretinaduringmovementsofthehead,bymovingtheeyesintheoppositedirection.Inotherwords, these reflexes serve to reduce retinal slip (movementof thevisual imageacross theretina). In afoveate animals like mice, the vestibulo-ocular reflex (VOR) uses vestibular input tocompensateretinalslipandtheoptokineticreflex(OKR)isdrivenbytheretinalslipitself.Wehaveproposed that a state-predicting feedback control (SPFC) framework could apply the elegance ofoptimal controlmodels to the compensatory eyemovement system.Here,we present aworkingversionoftheSPFC.Wechallengeourmodelbycomparingtheoutputtotheeyemovementsofmice(n=34).Themodelreproducesbehavioracrossarangeoffrequencies(0.1-3.2Hz)andamplitudes(0.5-8°) for primary reflexes (OKR andVOR) aswell as for two conditionswhere the reflexes functionsimultaneously (a matrix of 144 conditions). We also reproduced the response of the system tocomplexstimulisuchassumsofsines.Moreover,wechallengetheanatomicalbasisforthemodel:removalofoutputfromspecificpartsofthemodelarecomparedwiththeknowneffectsofneurallesions.Inourmodel,theOKRsystemlearnstocompensateforinaccuraciesoftheVOR.Thisexplainsthenon-linearsummationof theVORandOKRsystemsacrossdifferentstimulusconditions.SinceadaptationthenchangestheOKRcompensation,thisalsoexplainshowflocullarlesionsabolishVORadaptationbutnotVORperformance.


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IreneKuling,VrijeUniversiteit,HumanMovementSciences,Amsterdam

SensorymatchingerrorPeoplemakesystematicerrorswhenmatchingthelocationofanunseenindexfingerwiththelocationoftheindexfingeroftheotherhand,orwiththelocationofavisualtarget.Theseerrorsaresubject-dependentandconsistentover time.Theirorigin isunknown.Toseewhether theseerrors reflectmismatchesbetweentheproprioceptiveandvisualsenses(sensorybiases),wedesignedsetsoftasksthatinvolvedthesamematchingconfigurations,butdifferentactionstoreachthisconfiguration.Forexample,wecomparedmatchingerrorswhenmovingwiththeunseenindexfingertoavisualtarget,withmatchingerrorswhenmovingavisualtargettotheunseenindexfinger.We found that the matching errors are not invertible. Furthermore, moving both index fingerssequentiallytothesamevisualtargetresultsinadifferentmismatchbetweenthehandsthandirectlymatchingthetwoindexfingers.Fromtheseresultsweconcludethatsensorymatchingerrorsarenotsimplythesummationofsensorybiases.

MythePlaiser,VrijeUniversiteitAmsterdam,HumanMovementSciences,Amsterdam

Timingofsizeandweightinthesize-weightillusionThesize-weightillusionistheeffectthatsmallobjectsfeelheavierthanlargeronesofthesamemass.Ithasoftenbeensuggestedthatthisillusioniscausedbyamismatchbetweentheexpectedandactualweightof objects. If thiswere indeed the case,wepredict that the sizeof anobject needs tobeavailablepriortoliftingtheobject.Thisallowsanexpectationabouttheweighttobemadebeforehapticinformationabouttheweightisacquired.Weinvestigatedthisinanexperimentinwhichsizecouldonlybeperceivedthroughvision.Ineachtrial,wemadevisionavailablefora200msintervalstartingatvarioustimesfromliftonsetrangingfrom200mspriortoliftonsetuntilwhenthemaximumliftingheightwasreached.Surprisingly,thesize-weightillusionpersistedevenwhensizeinformationbecameavailableaslongas300msafterliftoff.After300ms,however,theillusiondiddecrease.Thisshowsthattherelativetimingofvisualsizeandhapticweightinformationiscrucial,butthatsizeinformationdoesnotneedtobeavailablepriortotheonsetoftheliftingaction.

KaylaStone,DepartmentofExperimentalPsychology,UtrechtUniversity,Utrecht

MeasuringbodyrepresentationinthelowerlimbsBody representations arise from the integration of multimodal bodily input. Consequently, theserepresentationscanbemeasuredinvariousways.Severalmethodsofinvestigationhavebeenusedtoassesstheunderlyingrepresentationofthehands.Forinstance,inataskwhereparticipantsareaskedtolocaliseunseenpartsofthehand,largedistortionsinhandlengthandwidthareobserved.Similar distortions are foundwhen participants are asked to judge tactile distances on the hand,suggestingthatthesemeasuresofbodyrepresentationareintimatelylinked.Yet,whenparticipantsareaskedtomakeexplicit,visually-basedjudgementsabouttheshapeofthehand,performanceisfairlyveridical.Butareallbodypartsrepresentedinasimilarmanner?Forexample,thelowerlimbsare functionally and structurally different from the hands, and therefore it is possible their bodyrepresentationmightbereflectiveofthesedifferences.Curiously,littleisknownabouttheunderlyingrepresentationofthelowerlimbs.Thus,whatdoestheinternalbodyrepresentationofthelegslooklike?Inthecurrentstudy, lowerlimbrepresentationwasmeasuredinthreetasks.Inthefirsttask,


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participantswereaskedtomakeimplicitjudgementsaboutthewidthandlengthofone’sownunseenleg,amannequinleg,andanon-corporealobjectpositionedhorizontallyunderalargemonitor.Inthesecondtask,participantsestimatedthedistancebetweentwotactilestimuliappliedtotheupperandlowerpartsoftheleg.Inthethirdtask,participantsmadeexplicitjudgementsaboutthewidthoftheirlegsbyindicatingwhether individuallypresentedimagesofa legwerewiderormoreslenderthantheirown.Resultsdemonstratethatthelowerlimbsarerepresenteddifferentlybasedonthebodyrepresentationmeasurementemployed.Theresultsarediscussedintermsofthemultimodalnatureofbodyrepresentation.

ThomasHulst,ErasmusUniversiteit,Neuroscience,Rotterdam

NoeffectsofcerebellarandM1transcranialdirectcurrentstimulationduringreachadaptationincerebellarpatients

People with cerebellar disease suffer from a number of specific motor impairments which aregenerally well-described, but for which the therapeutic options are limited. Several studies haveidentified transcranial direct current stimulation (tDCS) as a potential tool in the rehabilitation ofcerebellar disease. While a growing number of studies have investigated the effects ofcerebellar tDCS in healthy subjects, investigations of non-invasive brain stimulation in cerebellarpatientsarestillrare.Here,wetestedwhethertDCScouldalleviatemotorimpairmentsofsubjectswithcerebellardegeneration.Twogroupstookpartinthisstudy:twentyindividualswithcerebellardegeneration(meanage53.7years±SD10.8years)andtwentyage-matchedcontrols(meanage54.6years±SD11.2years).Astandardreachingtaskwithforcefield-perturbationswasusedtocomparemotor adaptation between groups and tomeasure the effect of stimulation of the cerebellumorprimarymotorcortex(M1).Thecerebellumwasstimulatedwithacurrentdensityof0.08mA/cm2,withtheanodalelectrodeplaced3cmlateraloftheinion.Theprimarymotorcortexwasstimulatedusingthesamecurrentdensity,withtheanodalelectrodeplacedatthepositionwherethefirstdorsalinterosseousmusclerespondedtoaTMSpulse.Allsubjectsweretestedduringeachstimulationtype(cerebellum, M1 and sham) with a break of one week between each of the three experimentalsessions.Asexpected,individualswithcerebellardegenerationhadasignificantlyreducedabilitytoadapttoperturbationsofthemotorsystemcomparedtohealthyage-matchedcontrols.Importantly,motor adaptationwasnot affectedby anodal stimulationof the cerebellumandM1 in cerebellarsubjects as well as control subjects. Voxel-based morphometry of T1 weighted MPRAGE scansrevealedstrongdegenerationoftheanteriorlobeandsuperiorpartsoftheposteriorcerebelluminthecerebellargroup,whichmayexplainthemotorimpairmentsofcerebellarsubjects.Thespecifictaskandstimulationparametersused in thisstudymayconstitutethe lackof tDCSeffects inbothgroups. For tDCS to become a valuable tool in the neurorehabilitation of cerebellar disease,stimulationeffectsshouldbemoreconsistentandpredictableacrosssubjectsandtasks.

JasperFabius,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

SpatiotopicupdatingfacilitatespostsaccadicperceptionIntrospectively,wehaveacontinuousstreamofvisualperception.Yet,astheneuralrepresentationofvisualinformationisinitiallycodedinretinotopiccoordinates,eyemovements(saccades)poseamajor problem for visual stability. If no visual information were maintained across saccades,retinotopic representations would have to be rebuilt after each saccade. It is currently stronglydebated what kind of information (if any at all) is accumulated across saccades, and when thisinformation becomes available after a saccade. Here, we use a motion illusion to examine the


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accumulationofvisualinformationacrosssaccades.Inthisillusion,anannuluswitharandomtextureslowlyrotates,andisthenreplacedwithasecondtexture(motiontransient).Withincreasingrotationdurations, observers consistently perceive the transient as large rotational jumps in the directionoppositetorotationdirection(backwardjumps).Wefirstshowthataccumulatedmotioninformationisupdatedspatiotopicallyacrosssaccades.Then,weshowthatthisaccumulatedinformationisreadilyavailableafterasaccade,immediatelybiasingpostsaccadicperception.Thecurrentfindingssuggestthatpresaccadicinformationisusedtofacilitatepostsaccadicperception.Theseresultsareinsupportof a forward model of transsaccadic perception, aiming at anticipating the consequences of eyemovementsonretinalinputandoperatingwithinthenarrowperisaccadictimewindow.

PaulZerr,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Remappinghigh-capacity,pre-attentivevisual-spatialworkingmemory.Ifwecouldonlyprocessvisualinformationwhileitwasavailablewewouldbeatafataldisadvantageasdynamicagentsinadynamicworld.Ashort-termmemorybufferallowsustoprocessvisualinputafter ithasdisappearedorwehavelookedaway.Stablevisualworkingmemoryhasavery limitedcapacity,however,and requiresslow,costly top-downattentionandselection.Thereexistsapre-attentive,high-capacitymemorybuffer thathasa centuries spanninghistoryas longas the listoftermsthatdescribeit,e.g.visualpersistence,visualanalog,iconicmemory,fragilememory,sensorymemory.Itrecentlysawarevivalofinterestthroughthedevelopmentoftheretro-cueparadigm:awayofprobingvisualworkingmemorywithoutdestroyingthismemorythroughthememoryprobeitself,similartothepartialreportparadigmbySperling(1960).Itenablesustoprobevisualworkingmemorycapacityincludingunstablememorytraces,whichdrasticallyincreasesmeasuredcapacitiesevensecondsafterstimulusoffset.Thepresentstudyinvestigateswhethertheseunstablememorytracescansurviveeyemovementsandthespatialremappingprocessthisentails.Weaskthequestionwhetheritemsneedtobeplacedinstableworkingmemorybeforetheycanberemapped.Todateremappingisthoughttobelimitedto3-4items(the‘magicnumber’forvisualworkingmemory).Wechallengethisstronglyheldbeliefbydemonstratinghigh-capacityremappingofspatialinformation.Further, we explore the time course of visual working memory through its different stages byemploying a dichoptic retro-cue viewing and masking paradigm. This holds implications for andinsightsintothehierarchicalprocessingofvisualinformationinthebrain.

MartijnSchut,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

UsingvisuallyguidedcorrectivesaccadestoinvestigatetranssaccadicmemoryDespitevarianceinsaccadeexecutionvisualsystemisabletoestablishcontinuitybetweensaccadesthrough corrective saccades. To successfully execute a visually guided corrective saccade, andestablishcontinuity,arepresentationofthesaccadetargetmustbeavailabletothevisualsystem.Inour current study, participants were tasked with remembering several shapes and performedsaccadestoacoloreddisc,whichmovedduringthesaccade,thereforeelicitingcorrectivesaccades.First,wefoundthatcorrectivesaccadeswereexecutedslowerwithincreasingworkingmemoryload.Inaddition,resultsshowthatshapeinformationis lessaccuratelyreportedwhenobservershadtoexecuteacorrectivesaccade.Therefore,wehavefoundevidencethatvisualcontinuityisdependentonvisualworkingmemoryandvisualinformationrelevanttovisualcontinuitymaybeprioritizedbythevisualsystemwhencompetingformemorystorage.


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JessicaHeeman,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

ExpresssaccadesUnder specific conditions visually-guided saccades canhavea latency that is shorter thannormal.These saccades are called express saccades (average latency 80 to 130 ms). In a first study weexplore eye movement behavior during anticipatory (<80ms), express (80 - 130 ms) and regularsaccades (>130 ms). During the experiment participants made saccades to a target at a knownlocation.Insometrialsthetargetwasaccompaniedbyadistractoratanunpredictablelocation.Theimplementedgap-paradigmandawarningsignalensuredahighpercentageoflowlatencysaccades.WeweresuccessfulintriggeringahighpercentageofexpressSaccade.ResultsshowedthataGlobalEffectwaspresentforexpresssaccades.Thisindicatesthattheoculomotorvectorismoderatedveryearlyonbyvisualinputandcounteractstheideathatexpresssaccadesaremerelytheexecutionofapreprogrammed oculomotor program. Also, the saccade latency distribution showed a clearbimodalitywhichhasoftenbeenobservedinmonkeystudiesbuthasrarelybeenobservedinhumans.Wehaveherebystartedexploringthepropertiesofexpresssaccadesandourinvestigationintowhat(ifatall)separatesexpresssaccadesfromregularsaccadesandanticipatorysaccades.

TabithaIseger,OnderzoeksinstituutBrainClinics,Nijmegen

TheDLPFC-sgACCnetwork:GettingattheheartofitMajor depressive disorder (MDD) is a chronic disease with a remitting and relapsing course.Antidepressant medication is the most common treatment MDD, however, the precise workingmechanism underlying this disorder remains unclear. Recent neuromodulation treatmentsdemonstrate that direct stimulation of the dorsolateral prefrontal cortex (DLPFC), dorsomedialprefrontal cortex (DMPFC), and subgenual anterior cingulate (sgACC) and vagal nerve stimulation(VNS)relatetoclinicalimprovement,suggestingconnectivityalterationsinthisneurovisceralnetworkto mediate antidepressant response. The international Study to Predict Optimized Treatment inDepression (iSPOT-D) is a multicentre study that collected EEG data for 1008 MDD patientsrandomizedto3differentantidepressantmedications.Inordertoinvestigatetreatmentresponses,as defined by a decline of >50% on the Hamilton Rating Score for Depression (HRSD17), weinvestigatedwhetherconnectivityinalphaandthetafrequenciesoftheDLPFC-DMPFC-sgACCnetworkdifferedpreand/orposttreatmentbetween:(i)patientsandcontrols,and(ii)respondersandnon-responders.Adifferenceinconnectivitywasfoundbetweenmenandwomen,preandposttreatment,inalphaandthetaconnectivity.Fortheta,MDDpatientsweredistinguishablefromcontrolsonbaseline.Formalerespondersonly,asignificanttimeeffectwasfound.Withrespecttomedication-typeeffects,noapparent effects were found. Exact results are confidential but will be presented. The genderdifferencesemphasizetheneedforaprioristratifyingbygenderforfutureimagingstudiesinmajordepression.Inaddition,anintroductionwillbegivenonourfutureresearch,focussingonconnectivitywiththevagalnerveandtherebytheeffectofdepression,neurostimulationandmedicationontheheart.


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SuryaGayet,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

VisualinputsignalingthreatgainspreferentialaccesstoawarenessVisual input that signals threat is inherently relevant for survival. Accordingly, it has beendemonstratedthatthreateningvisualinputelicitsfasterbehavioralresponsesthannon-threateningvisualinput.Consideringthatawarenessisaprerequisiteforperformingdemandingtasksandguidingnovelbehavior,wehypothesizedthatthreateningvisualinputwouldgainfasteraccesstoawarenessthannon-threateningvisualinput.Inthepresentstudy,weassociatedoneoftwobasicvisualstimuli,thatweredevoidofintrinsicrelevance(coloredannuli),withaversivestimulation(i.e.,electricshocks)followingaclassicalfearconditioningprocedure.Inthesubsequenttestphasenomoreelectricshocksweredelivered,andabreakingcontinuousflashsuppressiontaskwasusedtomeasurehowfastthesestimuliwouldaccessawareness.Theresultsrevealthatstimulithatwerepreviouslypairedwithanelectricshockbreakthroughsuppressionfasterthancomparablestimulithatwerenotpairedwithanelectricshock.

IrisSchutte,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Anticipatingrewardandprobability

The way humans behave is greatly affected by the principle expected utility, the combination ofsubjectivevalue(SV)oftheoutcomeofanact(isitrewarding?)andsubjectiveprobability(SP)ofthatoutcome.Thepresentstudyexaminedelectro-corticalrepresentationsoftheanticipationofSVandSPduringacuedGo/NoGoexperiment.Duringthistaskcueletterssignaledupcomingtargetletterstowhichparticipantshadtorespond.Theprobabilityoftargetletterappearanceafterthecueletterand the amount of money that could be won for correct and fast responses were orthogonallymanipulatedacrossfourtaskblocks.DuringthetalkIwillspecificallyfocusontherepresentationofprobability in thecortexandhow it interactswith rewardvalue. Iwill show that rewardandhighprobabilityequallyaffectafronto-centralevent-relatedpotentialcomponent.

HannahMulder,UniversiteitUtrecht,UtrechtInstituutforLinguisticsOTS,DepartmentofLangaugeandCommunication,Utrecht

Figuringoutwhattheyfeel:Theroleofnarrativefictioninunderstandingothers’mentalstates

“OnthemorningthelastLisbondaughtertookherturnatsuicide—itwasMarythistime,andsleepingpills,likeTherese—thetwoparamedicsarrivedatthehouseknowingexactlywheretheknifedrawerwas, and thegasoven, and thebeam in thebasement fromwhich itwaspossible to tie a rope.”(Eugenides1993,TheVirginSuicides)ThequoteaboveisthefirstsentenceofEugenides’novelTheVirginSuicidesandweareimmediatelysuckedin:whoisMary,whoisThereseandwhydidtheycommitsuicide?Thisexampleillustratesahallmarkofnarrativefiction:itisaboutautonomousintentionalagentsandtheir(inter)actionsandinorder to make sense of it, wemust engage in advanced social-cognitive processing. In this way,exposuretonarrativefictionprovidesuswithsocial-cognitivetrainingandthuscanpotentiallybeusedasatooltohoneourabilitiesinthisdomain.Indeed,variousstudieshavefoundbeneficialeffectsofexposuretonarrativefictiononmentalstatecomprehensioninadults(e.g.Kidd&Castano,2013),butthe extent to which these findings generalise to children has received less attention. Given that


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children are still developing their social abilities, it is relevant to determinewhether exposure tonarrative fiction may indeed provide additional input regarding how to interpret other people’smentalstates.The current study employs a confirmatory Bayesian approach to assess the relationship betweenmentalisingandexposuretonarrativefictionin8-to16-year-oldchildren.Mentalisingwasassessedusing both subjective and objectivemeasures. Exposure to narrative fictionwas assessed both interms of the general frequencywithwhich children consumenarrative fiction (as encountered inbooks,filmsandTV-series)andtheparticulartypesoffictionthattheyareexposedto.Withrespecttothislattercategory,adistinctionwasmadebetweenexposuretoeudaimonic(ortruth-seeking),vs.hedonic (pleasure-seeking) narrative fiction.We predicted that exposure to narrative fiction, andparticularlytheeudaimonicvariety,wouldbepositivelyrelatedtomentalising.Resultsofthisstudypartlyboreoutthesepredictions.Althoughthegeneralfrequencyofnarrativefictionexposurewasnotrelatedtomentalisingformostofthemeasures,exposuretoeudaimonicnarrativefictionwasgenerallypositivelyrelatedtomentalisingandmorestronglysothanexposuretohedonicnarrativefiction.Exposingchildrentoeudaimonicnarrativefictionmaythusbeaneffectivemeansofenhancingtheirunderstandingofothers’mentalstates.

RiannevanRooijen,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Beneficialeffectsofthemother’svoiceonnovelwordlearningininfantsInfantsseemtolearntheirnativelanguagequiteeasilyandwithoutmucheffort.However,learningalanguageisnotaseasyasitseems,anditcomprisesseveralimportantcomponents.Forinstance,aninfanthastoidentifyindividualwordsoutofcontinuousstreamsofsounds.Moreover,(s)hehastogeneratetherightword-objectassociations.Althoughallinfantslearntheirnativelanguage,thereisalargeindividualvariationinlanguagedevelopment.Itisthereforeinterestingtodeterminewhichfactors facilitate novel word learning. In the present study we focus on one of these possiblefacilitatingfactors,themother’svoice.Newbornsalreadyshowapreferencefortheirmother’svoiceoverthevoiceofastranger(DeCasper&Fifer,1980).Moreover,children’scomprehensionoffamiliarwords isbetterwhen theyhear themfromtheirmothercompared toa stranger (Parise&Csibra,2012).Ourquestioniswhetherthiseffectextendstothelearningofnovelwords.In this eye-tracking study,we testedwhether 24-month-olds learnt newword-object associationsmoreeasilyfromtheirmothercomparedtoastranger(theexperimenter).Infantsweretaughttwonewword-object associations, in a live setting (procedure similar toMa et al., 2011). Theirwordlearningwasassessedwithapreferentiallookingparadigm.Resultsshowedthatinfantsrequirelessexposuretotheword-objectmappingstoacquirewordlearningwhentaughtbytheirownmother.Infantswhoweretaughtbyastrangerdidlearnthenewword-objectassociationsaswell,yetonlylaterduringtheexperiment.Thisindicatesthatthemother’svoiceboostslearningofnewwords.Attheindividuallevel,wetriedtoexplainsomeofthevariationinwordlearningabilitiesbylookingatcorrelationswithproductivevocabularysize.Wefoundthatindividualvariationinwordlearningabilitiespositivelycorrelateswithcurrentproductivevocabularysize.Infantswithabiggerproductivevocabularysizewerebetteratformingthenewword-objectassociations.


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CarolineJunge,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Speakerfamiliarityaidsbothnovelwordencodingandmapping:ERPevidenceBackground:Forlanguageacquisition,thematernalvoiceplaysaspecialrole.Itistheonlyvoicethatneonateshavemostexperiencewithandpreferoveranyothervoice.Wheninfantshearmaternalspeech,theyprocessthisvoicefasterandincreaseactivationinbrainareasrelatedtolanguageandattention.Maternalspeechplaysaroleinwordprocessingaswell:recentresearchsuggeststhatinchallenging situations, infants only recognize words uttered by their caretaker (compared to anunfamiliarperson;word-forms:Barker&Newman,2004;knownwords:Parise&Csibra,2012).Butdoestheadvantageofmaternalspeechalsoextendstoearlywordlearning?ThecurrentstudyusesERPstostudytheeffectofmaternalspeechonboththeprocess(wordandobjectencoding)andtheresult(word-objectmapping)ofnovelwordlearning.Design:Wetested44monolingual11-month-olds(range303-361days;23girls).Halfofthemlistenedtotheirownmother’svoice(familiarvoicecondition);otherhalflistenedtothesamestimuli(e.g.,forthem,unfamiliarvoicecondition).Auditorywordswerepre-recordedtokensofdefinitearticlespluspseudo-words.Atrainingphasecomprisedtwonovelobject-novelwordpairs,eachpresentedeighttimes.Thetestphaseshowedthesameobjectsandwordsagain,butcomparedtotraining,onlyhalfofthepairingswerecongruent,andotherswereincongruent(e.g,switchedword-objectpairings).WerecordedERPstime-lockedtotargetwordonsetthroughouttheexperiment(-200–800ms).Results:Forwordencoding,weexaminedtheN200-500,whichisaninfantERPcomponentsensitivetoword-formrepetition(Junge2012).Inbothvoiceconditions,thereisadecreaseofpositivitywithrepetition(i.e.,increaseofN200-500).Thisdecreaseislargestinthefamiliarvoicecondition,andmainlydrivenby the first block of words in the maternal voice condition, which shows the largest positivity.Considering that the N200-500 is associated with word familiarity, a larger initial positivity thuspossiblyreflectsthatinfantstreatwordsasmoreunfamiliarwhenutteredbytheirmotherthanbyanunfamiliarspeaker.Tomeasuretheeffectofmaternalvoiceonword-objectpairings,weexaminedERPstocongruentvs.incongruentpairings.Onlyinfantsfromthefamiliarvoiceconditionshowedatypicalcongruityeffect(i.e.,N400)over leftelectrodes,whereas infants in theunfamiliarvoicecondition fail toshowanysignificantN400atanyhemisphere.Together,resultsshowthatmaternalvoiceboostsbothwordencodingandword-to-objectmapping.


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SitaterHaar

Causalmechanismsinbirdsonglearningasamodelforhumanspeechacquisition(VENIproposal)Humanlanguageacquisitionisacrucialaspectofinfantcognitivedevelopment.Unfortunatelyabout5-7% of the children are affected by language development problems, for example SLI (SpecificLanguageImpairment).Thecauseofsuchproblemsisoftennotverywellunderstood.Itisexpectedthat a combination of genetic and environmental factors usually underlie speech and languagedevelopment problems. Disentangling genetics and environment in human infants is extremelychallenging,ifpossibleatall.Therefore,Iproposetouseananimalmodeltostudydevelopmentinacontrolledsetting.Mostanimalsystemsarenotappropriateasmodelsforspeechdevelopmentastheirvocalizationsaremostlyinnate.Songbirdshoweverdolearntheirvocalizationsbymeansofacombinationofinnatebiasesandexperience(similartohumans)andarethereforeabettermodel.ByusingsongbirdsasamodelIaimtodisentanglethecausaleffectsofexperience-dependentand-independentfactorsonvocallearning.Correlativedataalsosuggeststhatsleepandlateralizationmaybeassociatedwithsonglearninginsongbirdsandspeechacquisitioninhumaninfants,butagainthecausal relationship is unknown. Furthermore, lateralized neural activity is associated with bothexperience-dependentand-independentprocessesbutagainthecausalrelationisunknown.Finally,theleftandrighthalfofthebrainarealsodifferentiallyactivatedduringsleep,suggestingallthesefactorsprobably interact,butthemechanismisunknown. Iaimto investigatethese issuesusingacombinationofneuralandbehaviouralmeasurements.Iwillusesleepdeprivationtoinvestigatethecausaleffectofsleeponlearning.Furthermore,Iwilluseoptogeneticsinordertostudycausaleffectsoflateralizationbymanipulatingneuralactivityineithertheleftortherighthemispherespecificallyduringsongexposureduringdevelopment.OncethecausaleffectsonsonglearningareknownIaimto translate these findings back to humans by means of noninvasive neural and behaviouralmeasurementstostudyifsimilarresponsepatternscanbefoundinhumaninfantsandiftheycouldbeusedasearlymarkersfordevelopmentalproblems.

AnoukvanderWeiden,UniversiteitUtrecht,SHOP,Utrecht

Measuringautomaticassociationsinlongitudinaldesigns-Doesthelexicaldecisiontaskstandthetestoftime?

Whenwestriveforlong-termgoals(e.g.,healthyeating,savingmoney,reducingenergyconsumption,or maintaining a romantic relationship), we often get in conflict with our short-term goals (e.g.,temptingsnacks,must-haves,gettingwarm,orbeingattractedtosomeoneelse).Althoughwemayinitiallybeabletoresistshort-termtemptations,thisoftenbackfiresinthelongrun.Thatis,previousresearchsuggeststhatourwillpowerislimitedandthattheresistanceofonetemptationleadstothedepletionofwillpower,causingustoletourselvesgowhenconfrontedwithanothertemptation.Inlinewiththisnotion,recentresearchsuggeststhatinsteadofinvestingmoreeffortincontrollingtheirbehavior,peoplebenefitmorefromeffortlesscontrolstrategies,suchastheformationofgoodhabits.Forthispurpose,weaimtoinvestigatehowautomaticassociationsbetweencontextandbehavior(habits)developovertime,andhowwecanacceleratethisprocess.However,thisraisesthequestionwhether measures of automatic behavior (such as the commonly used lexical decision task) aresuitableforlongitudinalresearchdesigns.Typically,inalexicaldecisiontask,behavior-wordsaremoreaccessible(andthusrecognizedfaster)afterbeingbrieflyprimedwithassociatedcontext-words.Yet,the repeatedpresentationof target stimulimayenhance their accessibility to theextent that theaccessibilitycannolongerbeenhancedbycontext-primes.Asafirsttestofthestabilityofprimingeffectsinthelexicaldecisiontaskovertime,wehadparticipantsperformalexicaldecisiontaskforfivedaysinarowinwhichtheywerepresentedwithfourword-pairrepetitionsperday(resultingin


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atotalof20word-pairrepetitions).Toestablishassociationsbetweencontextandbehaviorwords,participantsformedimplementationintentionsthatspecificallyspecifiedbothcontextandbehavior(e.g.,ifIamhavinglunch,Iwilleatanapple).Wealsoincludedword-pairsthatarestrongly(guitarandmusic)orweakly(airandmusic)associated.Resultsshowedthattherewasareliableassociationbetween the context and behavior as specified in the implementation intentions, although theassociationstrengthwasweak.However,associationstrengthdidnotvaryovertime,suggestingthatprimingeffectscanstillbedetectedafterrepeatedpresentation.

SamanthaAntusch,UniversiteitUtrecht,SHOP,Utrecht

TheInfluenceofRewardingActionsonIntentionalBindingOperant actions and their subsequent effects are shifted together in temporal perception. Thisintentionalbindingeffectisassumedtoservethehumanperceptionofcausalityandisconsistentlyusedasanimplicitmeasurementofsenseofagency.Usingmonetaryrewards,weinvestigatedtheinfluenceofvaryingthenatureoftheactiononintentionalbinding.Itwashypothesizedthatexecutingamore rewardingversusa less rewardingaction results in strongerbinding. Ina counterbalancedwithin-subjectsdesign,participantslearnedthatakeypresswasmoreoftenrelatedtoarewardthananalternativekeypresswhilebothhadthesameneutraltoneasaresult.Confirmingthehypothesis,executinganactionthatwaslearnedtobemorerewardingascomparedtolessrewardingincreasedtonebindingonasubsequentLibetclocktasksignificantly.Thatis,theresultsofferimportantnewinsights into the underlying working mechanisms of intentional binding and the development ofagenticexperiences.Indetail,intentionalbindingseemstonotsolelybeinfluencedbythevalenceoftheaction-outcomebutalsobythenatureoftheprecedingaction.Findingsareinlinewithforwardmodelsofmotorpredictionandgiverisetoarangeofempiricalquestionsregardingtheimportanceofactionnatureandaction-outcomevalenceinthecontextoftemporalbinding.

JasperH.B.deGroot,UtrechtUniversity

LearningtoUnderstandHumanOlfactoryCommunicationHumansusemultiplesensestonavigatethesocialworld.Amongthese,oursenseofsmellisarguablythemostunderestimatedone.Oneintriguingfunctionofthesenseofsmellisitssocialcommunicativefunction.Researchhasshownthathumanodorscanconveyinformationaboutarangeofstates(e.g.,emotions,sickness)andtraits(e.g.,individuality,gender).Yet,whatunderliesthecommunicabilityofthese states and traits via smell? I aim to fill this explanatory gapby furnishing a framework thathighlightsthedynamicandflexibleaspectsofhumanolfactorycommunication.Asanalternativetoa“hardwired”pheromone-perspective,Ipositthathumanolfactorycommunicationdependsonamoreflexiblecombinationofnatureandnurture.Frombirth,weareendowedwithanolfactorysystemthatcanrapidlylearntoassociatesmellswithcertainoutcomes(e.g.,good,bad,tasty,scary);yet,whetherweactuallydeveloptheseassociationsdependsonthesituationswefindourselvesin,andwhetherestablishinganodor-informationlinkisrelevanttous(e.g.,basedonourgoals,internalstate,oronthecontextathand).Suchamodelshouldnotonlyhelptointegratepastresearchonhumanolfactorycommunication,but italsoopensnewavenues for future researchon this fascinating,yet todatepoorlyunderstoodfield.


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IsabellMeier,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Naltrexoneincreasesnegatively-valencedmimicryinresponsetohappyfacialexpressionsPositive social cues, likehappy facial expressions, activate thebrain’s reward systemand indicateinterest insocialaffiliation.Facialmimicryofemotions,which is thepredominantlyautomaticandunconscious imitation of another person’s facial expression, has been shown to promote socialaffiliation.Ithasbeendemonstratedrepeatedlythattheopioidsystemisvitaltosocialaffiliationinrodents,but there is lessevidence inhumans.We investigatedwhethera50mgadministrationofnaltrexone,anopioidantagonistwithhighestaffinityforthemu-opioidsystem,modulatesemotionalmimicry.Apassiveviewingtaskwithdynamicfacialexpressionswasusedinarandomizedplacebocontrolledbetween-subjectsdesign.Mimicrywasmeasuredwithelectromyography(EMG)onthreefacialmuscles, thecorrugator supercilii and thedepressor jawmuscle,associatedwithnegatively-valenced emotions, and the zygomaticus major, which is activated during smiling. The resultsdemonstrateanincreaseofnegatively-valencedmimicry(corrugatoranddepressor) inresponsetohappyfacialexpressionsafternaltrexonecomparedtoplacebo,consistentwithloweredinterestinsocial interaction or affiliation. Our findings provide evidence for a role of the opioid system inmodulatingautomaticbehavioralresponsestocuesofrewardandsocialinteraction,andtranslatetorodentmodelsofthemu-opioidsystemandsocialaffiliation.

BarrieKlein,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

SpatialattentionmodulatesrepresentationsofvisualspaceinhumansSpatialattentionallowsustoselectrelevantvisualinformationbasedonitslocationinthevisualfield,improving perception of the attended information and altering the neural response to theinformation.Wewill discuss how spatial attentionmodulates the cortical representationof visualspace, using a combination of ultra-high field fMRI (7 Tesla), computational modeling andpsychophysics.Weshowthatattentionbiasesthespatialselectivityofneuralpopulationstowardstheattendedlocationinthevisualfield,expandingthecorticalrepresentationofattendedinformation.Thismodulationofthecorticalrepresentationincreasesupthevisualhierarchy.Wemodeltheeffectsofspatialattentionasaninteractionbetweenanattentioncomponent(attentionfield)andstimulus-drivenpropertiesofvisualfieldmaps(populationreceptivefields).Thisapproachrevealsthatthesizeof the attention field is relatively constant across the visual hierarchy and that attention isimplementedsimilarlyacrossthevisualhierarchy.Additionalpsychophysicalstudiesrevealthatthesameattentionfieldmodelcapturessomeoftheeffectsofspatialattentiononhumanperceptionaswell. Taken together, these results demonstrate that attention acts similarly across the visualhierarchy,whichsuggeststhattheattentionfieldoriginatesfromasinglesource.Despitethesimilarityof attention fieldsacross thehierarchy, thereare still importantdifferencesbetweenareas in theeffectsofattention,becausereceptivefieldpropertiesvarybetweenvisualfieldmaps.

WietskeZuiderbaan,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Changeblindness:theroleoflow-levelandhigh-levelimagerepresentationsOur internal representation of an image is not as detailed as we intuitively experience. This isexemplified by the fact that subjects fail to detect large changes in a visual scene, i.e. change-blindness.Currenttheoriesproposethattheinternalrepresentationcapturesthegist(interpretationofthe image)andthatchanges ingistaredetectedfaster.Ontheotherhand,weknowthatearly


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visualcortexrepresentscontrastenergy.Hereweinvestigatetheroleofthelow-levelfeaturecontrastandthehigher-levelfeaturegistonourinternalrepresentation.MethodsWe measured reaction times (RTs) in a flicker-task using the change-blindness paradigm(Rensink,1997).Wealternatedtwoimages(108image-sets)andthesubjects(n=60)indicatedwhenandwheretheysawthechange.TheimagesweretakenfromtheBerkeleySegmentationDatasetandBenchmarkdatabase(Martinetal,2001).Thisdatasetcontainsmanualsegmentationswheresubjectsidentifiedthemostimportantaspectsoftheimage.Weusethesesegmentationsasameasureofgist.Foreveryimage-set,wecomputedboththechangeinlocalRMS-contrastandthechangeingist.Fromthesechangeswedefined4conditions: image-setsthatare‘low’and‘high’ intheirdifferencesforcontrastandgist,respectively.Wecontrolledforsize,eccentricity,localcontrastandluminanceofthechangedarea.ResultsRTswerefasterwhenimage-setswerehighingistchange(medianincreaseRT=2.2sec),orhighincontrastchange(medianincreaseRT=1.75sec).Furthermore,RTswerefastestwhenimage-setswerebothhighingistchangeandhighincontrastchange(medianincreaseRT=5.0sec).DiscussionOur results suggest that the internal representation of the image, asmeasuredwith achange-detectionparadigm,isnotonlyinfluencedbyhigh-levelimageinterpretation(gist),butalsobylow-levelimagestatisticssuchascontrast.

MaartjedeJong,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

IntracranialrecordingsofoccipitalcortexresponsestoillusoryvisualeventsAmbiguousvisualstimulielicitdifferentperceptualinterpretationsovertime,creatingtheillusionthata constant stimulus is changing. We investigate whether such spontaneous changes in visualperception involveoccipitalbrainregionsspecializedforprocessingvisual information,despitetheabsenceof concomitant changes in stimulation.Spontaneousperceptual changesduringbinocularrivalry or ambiguous structure-from-motion were compared with stimulus-induced perceptualchangesthatoccurredinresponsetoanactualstimuluschange.Intracranialrecordingsfromhumanoccipital cortex revealed that spontaneous and stimulus-induced perceptual changes were bothassociatedwithanearlytransientincreaseinhigh-frequencypowerthatwasmorespatiallyconfinedthanalatertransientdecreaseinlow-frequencypower.Wesuggestthattheobservedhigh-andlow-frequencymodulationsrelatetoinitiationandmaintenanceofapercept,respectively.Ourresultsarecompatible with the idea that spontaneous changes in perception originate from competitiveinteractionswithinvisualneuralnetworks

JimMaarseveen,UniversiteitUtrecht,PsychologischeFunctieleer,Utrecht

Spatialselectivityofthedurationafter-effectAdapting to the duration of a visual stimulus causes the perceived duration of a subsequentlypresentedstimuluswithaslightlydifferentdurationtobeskewedawayfromtheadaptedduration.Thispatternofrepulsionfollowingadaptationissimilartothatobservedforothervisualproperties,suchasorientation,andisconsideredasevidenceforduration-selectivechannels(Heron,etal.2012).Here, we investigated the spatial selectivity of these duration channels by varying the distancebetweenadaptationandteststimulus.Observerswerepresentedwitha100repetitionsofaGaussianblob (σ = 0.75°) located 8° above a central fixation cross, lasting either 160 or 640ms. Followingadaptation,participantscompletedadurationcomparisontaskwitheachtrialstartingwithfourtop-upsfollowedbythepresentationofanauditoryreference(320ms)andavisualteststimulus.The


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duration of the visual test stimuluswas varied using a staircase procedure to obtain the point ofsubjectiveequality.Toinvestigatethespatialextentoftheadaptationeffect,thedistancebetweenadaptation and test stimuli was varied between 0° and 15°. Our results show a clear durationadaptationeffect:theteststimuluswasperceivedtohavealongerdurationfollowingadaptationtoashorterduration,andashorterdurationfollowingadaptationtoalongerduration.Importantly,thisadaptationeffectoccurredatallmeasureddistances,andtherewasnoevidenceforadecreaseinthestrengthofadaptationatlargerdistances.Weconcludethatdurationadaptationisposition-invariant,transferringto locationsseparatedbymorethan10°fromthelocationoftheadaptationstimulus.Given the spatial extent of the adaptation effect, it seems unlikely that the proposed durationchannelsarerepresentedin lower levelretinotopicallyorganizedvisualareas, insteadsuggestingalaterlocus.

Helmholtz Retreat 2016 · Proceedings of the 8th Helmholtz Retreat 5 Program Locations: All...

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