TALKSESSION1

JesseRissman

Striatalcontributionstoexplicitremembering:Effectsofmemorystrengthanddecisionconfidence

JesseRissman&AnthonyD.Wagner

Dept.ofPsychologyandNeurosciencesProgram,StanfordUniversity

Functionalneuroimaginginvestigationsofepisodicretrievalconsistentlyidentifya

networkofprefrontal,parietal,andmedialtemporalloberegionsthatexhibit

greateractivitywhenindividualsrecognizepreviouslyencounteredstimulithan

whentheyperceivestimuliasnovel.Interactionsbetweenstriatalstructuresand

bothprefrontalcortexandthemedialtemporalloberaisethepossibilitythatbasal

gangliaprocessescontributetoexplicitremembering.Herewereportconverging

evidencefromtwofMRIstudiesthatbilateralregionsoftheventralstriatum(VS)

arehighlysensitivetotheperceivedmnemonicstatusofitemsduringexplicit,but

notimplicit,retrievaltasks,andthatthemagnitudeofactivationvarieswith

memorydecisionconfidence.Inthefirstexperiment,participantswerescanned

whileratingtheirlevelofrecognitionmemoryconfidenceforfacestimuliona5‐

pointscale.AreasofVSexhibitedenhancedactivitytooldvs.newstimuli.

Importantly,ratherthanshowingamonotonicscalingofactivitywithmnemonic

strength,activitylevelsscaledwiththedistanceofparticipants’responsesfromthe

old/newdecisionbound––activitylevelsweregreaterforhitsandcorrectrejections

thatweremadewiththehighestconfidencerelativetothosemadewithlow

confidence.Bycontrast,whenparticipantsmademale/femalejudgmentsonstudied

andnovelfaces(i.e.,implicitretrieval),theold/neweffectsinVSwereabolished.A

secondexperimentrevealedsimilarlyrobustold/neweffectsinoverlappingregions

ofVSwhileparticipantsmadesourcerecollectionjudgmentsaboutstudiedand

novelobjectstimuli,butnotwhiletheymadesemanticjudgments(i.e.,implicit

retrieval)aboutthesestimuli.Takentogether,thesetwostudiesdemonstratethat

regionsofVSshowamarkedsensitivitytothemnemonicstatusofstimuliduring

explicitmemorytasks.Thedependenceoftheseeffectsontheexplicitretrieval

demandsofthetaskssuggeststhatVSmayplayaroleingoal‐directedcontrol

processesthatfacilitatetherecoveryofmemories,evaluatetheretrieved

information,orselecttheappropriatebehavioraldecisions.Alternatively,the

activityinVSmaytrackthelevelofintrinsicrewardassociatedwithsuccessfultask

performance.Functionalconnectivityanalysespromisetofurtherinformhow

interactionsbetweenVSandprefrontal,medialtemporal,andmidbrainstructures

contributetoexplicitremembering.

Fundingsources:NIMH(R01–MH080309;R01–MH076932);MacArthur

Foundation’sLawandNeuroscienceProject.

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BradleyVoytek

Prefrontalcortexandbasalgangliacontributionstovisualworkingmemory

BradleyVoytek&RobertT.Knight,UCBerkeley

Visualworkingmemory(VWM)isaremarkableskilldependentonthebrain’s

abilitytoconstructandholdaninternalrepresentationoftheworldforlater

comparisontoanexternalstimulus.Prefrontalcortex(PFC)andbasalganglia(BG)

interactwithinacorticalandsubcorticalnetworksupportingVWM.Weusedscalp

electroencephalographyinagroupofpatientswithunilateralPFCorBGlesionsto

showthattheseregionsplaycomplementarybutdissociablerolesinVWM.PFC

patientsshowbehavioralandelectrophysiologicaldeficitsmanifestedby

attenuationofextrastriateattentionandVWM‐relatedneuralactivityonlyfor

stimulipresentedtothecontralesionalvisualfield.Incontrast,patientswithBG

lesionsshowbehavioralandelectrophysiologicalVWMdeficitsindependentofthe

hemifieldofstimuluspresentationbuthaveintactextrastriateattentionactivity.

Furthermore,patientswithBGlesionsareperformsignificantlyworseduringthe

firstfewtrialscomparedtoPFCpatientsandcontrols,despiteanexplicit

comprehensionofthetaskrulesandrequirements.Theresultssupportamodel

whereinthePFCiscriticalfortop‐downintrahemisphericmodulationofattention

andVWMwiththeBGinvolvedinglobalVWMprocesses.

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DarleneArcher

IndividualDifferencesinControllingTop­downAttentionalSelection

DarleneArcher&JoyGeng,Ph.D.

UniversityofCalifornia‐Davis

Attentioncanbedirectedvoluntarilybygoalrelevantinformationoritcanbe

capturedinvoluntarilybyperceptuallysalientinput.Forexample,themaintenance

oftargetinformationinWMcanfacilitatestrategicallocationofattentiontoanitem

thatfitstargetcriteriaorawayfromitemsthatfailtomeettargetcriteria

(Woodman&Luck,2007).Similarly,eyemovementdatasuggeststhattopdown

attentionalselectioncanbecontrolledwhenindividualsknowthataperceptually

salientobjectcannotbethetarget(Geng&DiQuattro,inpress).Wemeasured

individuals’visualworkingmemorycapacityusingamodifiedversionofthechange

detectiontask(Luck&Vogel,1997).Thenweexaminedindividuals’performance

andeyemovementsinavisualsearchtaskwhereacueprovidedinformationabout

thesalienceofeitherthetargetordistractoronatrial‐by‐trialbasis.High‐capacity

individualsdemonstratedgreaterabilityoverridingattentionalcapturethanlow‐

capacityindividuals,particularlywhenthecueindicatedthatthedistractorwas

salient.

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ElissaAminoff

Factorsthatpredictindividualdifferencesincriterionshiftinginrecognition

memory

Aminoff,E.,Clewett,D.,Freeman,S.,Grafton,S.,&Miller,M.

UCSantaBarbara

Avarietyofinformationisusedtoestablishacriterioninrecognitionmemory,such

asthemnemonicqualitiesofthememory,probabilitiesofagivenenvironment,and

consequencesofthejudgment.Iftheevidenceofastimulussurpassesthecriterion,

itisconsideredanoldstimulus.Thepresentstudymodulatedtheenvironmental

informationgivenaboutastimulus,specificallythelikelihoodthatitwasold(either

70%or30%).Inresponsetothisinformation,someparticipantsswitchedtheir

criterionbasedontheprobabilityinformation(aliberalcriterioninthe70%

condition,andconservativecriterioninthe30%condition),whereasother

participantsusedthesamecriterionregardless.Ourgoalwastoexaminetheneural

andbehavioralfactorsthatcouldpredictwhetheraparticipantswitchedcriterion.

Thisstudyconsistedofapoolof95participants,70%ofwhichwerecombat

experiencedofficersofthearmy;twoindependentmemorytests;functionalMRIat

test;andabatteryofquestionnairesthatassessedpersonalitytraits,cognitivestyle,

demographicinformation,andmentalstateduringtesting.Ourresultsindicated

thatbehavioralmeasures(includingpersonalityandcognitivecharacteristics)could

accountfor35‐42%oftheindividualvariability.Differentialneuralactivityanalyzed

throughROIanalysiscouldaccountforanadditional24%ofthevariabilityabove

thatofthebehavioralmeasures.Theseresultsprovideacomprehensive

examinationoftheunderlyingfactorsthataccountforindividualvariabilityin

criterionshifting.Moreovertheresultsprovideacleardemonstrationthat

neuroimagingisacriticaltooltoexamineindividualdifferencesinbehaviorover

andabovepaperandpencilassessments.

SupportedbyArmyResearchOfficeContractW911NF‐07‐1‐0072withthe

InstituteforCollaborativeBiotechnologiesatUCSantaBarbara.

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BryceMander

SleepRestorestheHumanBrainCapacitytoLearn

BryceA.Mander1,SangeethaSanthanam1,MatthewP.Walker1,21SleepandNeuroimagingLaboratory,DepartmentofPsychology,2HelenWillsNeuroscience

Institute,UniversityofCalifornia,Berkeley,CA94720

Incontrasttoconsolidation,theroleofsleepinfacilitatingtheinitialstageof

memoryencodingremainslargelyuncharacterized.NREMsleep‐oscillationshave

beenproposedtorestoreneuraldynamicssupportingoptimalmemoryprocessing.

Herewetestthehypothesisthatepisodiclearningabilitydeteriorateswith

continuedtimeawake,butthatNREMsleep‐spindleoscillationsrestoresuch

hippocampalencodingcapacity.Thirty‐nineparticipants(20.7±0.3years)

performedtwoseparateepisodicmemory‐encodingsessions:12‐noonand6PM.

Afterthefirstlearningsessionparticipantseitherremainedawakefor6‐hr(No‐Nap

group;n=19),orobtaineda100‐minutehigh‐densityEEGmonitoredsleepperiod

(Nap‐group;n=20).Episodiclearningabilitywasmeasuredusingaface‐name

associativeencodingtaskknowntodemandhippocampal‐dependentprocesses.

Face‐nameencodingcapacitydeterioratedacrossthe6hrwakingintervalintheNo‐

Napgroup,yetsleepblockedthisdeteriorationintheNap‐group,andactually

enhancedlearningcapacity(p=0.049).Theenhancementoflearningcapacityinthe

Nap‐groupcorrelatedsignificantlywithNREMstage‐2(p=0.015),andspecifically

thenumberoffastsleepspindlesoverleftprefrontalcortex(p=0.018).EEGsource‐

mappinganalysisofthesespindlesrevealedatime‐seriesloopofcurrent‐density

activitybetweenmedial‐temporalandleftprefrontalregions.Together,these

findingsdemonstratethatepisodiclearningabilityisnotstableacrossawakingday,

deterioratingovera6‐hrperiod.However,sleep,andspecificallyNREM‐stage‐2fast

spindles,restoredthishippocampal‐dependentencodingcapacity,withsource

analysissuggestingthisrestorationmaybedependentoncoordinatedfronto‐

temporalactivityduringtheseburst‐oscillations.Suchevidencesupportsamodelof

sleep‐dependenthippocampal‐neocorticalmemorytransfer,which,asa

consequence,reinstatesefficientnext‐daylearningability.

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BenjaminLevy

Cognitivecontrolandrightventrolateralprefrontalcortex

BenjaminJ.Levy&AnthonyD.Wagner

Dept.ofPsychologyandNeuroscienceProgram,StanfordUniversity

Delineatingthefunctionalorganizationofprefrontalcortexiscentraltoadvancing

neuralandpsychologicalmodelsofgoal‐directedcognition.Overthepastdecade,

considerablefunctionalneuroimagingdataindicatethatspecificformsofcognitive

controlareconsistentlyassociatedwithdistinctsubregionsofventrolateral

prefrontalcortex(VLPFC).Whilethishasledtoincreasinglyspecifiedmodelsofleft

VLPFCfunctioning,lessisknownaboutfunctionaldifferentiationwithinright

VLPFC.Recently,twoproposalshavedominatedtheoriesabouttheroleofright

VLPFC:stoppingofmotorresponsesandreflexiveorientingtoabruptperceptual

onsets.Atpresent,itremainsunclearwhethertheseprocessesactivatethesameor

distinctVLPFCsubregion(s),andwhethertheseputativeprocessesareinherently

linked(e.g.,stoppingtypicallyrequiresorientingtoaninfrequentstopcue).

Moreover,itisunclearwhetherandhowtheseperspectivescanaccountforthe

broadrangeofgoal‐directedtasksthatactivaterightVLPFC.Forexample,itisnot

obvioushoweithercouldaccountforthefrequentobservationofrightVLPFC

activationduringprocessingof,andepisodicmemoryfor,visuospatialstimuli.Here

wereviewthesedisparateliteraturesthroughmeta‐analysisofrightVLPFC

function.ALEanalysesofthestoppingandreflexiveorientingtasksrevealedoverlap

withintheinferiorfrontaljunctionalongwithdivergenceinmoreinferiorVLPFC

subregions.Theseresultsadvanceunderstandingofthefunctionalheterogeneity

withinrightVLPFC,andwediscusshowthisheterogeneityrelatestohierarchical

theoriesofPFCfunctionalorganizationandcognitivecontrol.

FundedbyNIMH(5R01–MH080309andF32‐079648).

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LauraLibby

UnitizationEffectsonEpisodicMemoryinSchizophrenia

LauraA.Libby1,CharanRanganath1,AndrewL.Haskins1,IanRamsay2,CameronS.

Carter2,J.DanielRagland21Psychology,UniversityofCaliforniaatDavis,Davis,CA,2PsychiatryandBehavioralSciences,

UniversityofCaliforniaatDavis,Sacramento,CA

Patientswithschizophreniamaybeimpairedatrelationalmemory(remembering

relationshipsamongstitemsandthecontextinwhichtheywereencountered),even

whenmemoryforitemsisintact.Thisstudyinvestigatedtheimpactofreducing

relationaldemandsbyhavingpatientsencodepairsofitemsasasingleunit(i.e.,

“unitization”).Preliminarydatawereobtainedonninepatientsandfivecontrols

whostudied280nounpairs.Pairswereprocessedeitherasasingleunitby

requiringformationofacompoundword(“unitized”trials)orasseparateunitsby

encodingthemaspartofasentence(“non‐unitized”trials).Participantswere

subsequentlyadministeredanassociativerecognitiontaskincludinginitialtarget

pairs,and280recombinedpairs.Receiveroperatorcharacteristics(ROC)were

calculatedtoobtainestimatesofrecollectionandfamiliarity.Unitization

successfullyincreasedfamiliarity‐basedretrieval,andthismemoryfacilitationeffect

(p<0.05)wasofsimilarmagnitudeforpatientsandcontrols.Incontrast,recollection

wasnotfacilitatedbytheunitizationprocedure,andpatients’recollectionof

unitizedandnon‐unitizedinformationremainedclosetozero.Thisstudyprovides

preliminaryevidencethatpatientsmaybenefitfromremediationstrategiesthat

encouragethemtoencodemultipleitemsasasinglecombinedrepresentationto

reducerelationalmemorydemandsandfacilitatefamiliarity‐basedretrieval.

Additionaldatawillbeobtainedtoconfirmthesepreliminaryfindings,andfuture

fMRIstudieswillinvestigatethehypothesisthatpatientdeficitsinhippocampal

versusperirhinalfunctionmayaccountforthispatternofbehavioralfindings.

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JacobBollinger

Deficitsinexpectation­drivenfunctionalconnectivityunderliememory

impairmentsinnormalaging.

JacobBollinger,MichaelT.Rubens,EdrickMasangkay,andAdamGazzaley

W.M.KeckCenterforIntegrativeNeurosciences,UniversityofCalifornia,SanFrancisco

Expectationsgeneratedbypredictivecuesincreasetheefficiencyofperceptual

processingofcomplexstimuli(e.g.faces,scenes),howevertheimpactthatthishas

onworkingmemory(WM)andlong‐termmemory(LTM)hasnotyetbeen

investigated.Here,healthyyoungandolderadultsperformeddelayed‐recognition

tasksthatdifferedonlyinstimulus‐categoryexpectations,whilebehavioraland

functionalmagneticresonanceimaging(fMRI)datawerecollected.Univariateand

functional‐connectivityanalyseswereutilizedtoexamineexpectation‐driven,pre‐

stimulusneuralmodulation,thenetworksthatregulatethismodulationand

subsequentmemoryperformance.AnalysisofbehavioraldatarevealedageXWM

andageXLTMinteractions,suchthatpredictivecategorycuingwasassociatedwith

enhancedWMandLTMforfacesinyoungeradults,whilepredictive‐cueassociated

WMorLTMbenefitswereabsentinolderadults.Inyoungeradults,baselineactivity

shiftswerepresentinaface‐selectiveregionofthevisualassociationcortex(i.e.,

fusiformfacearea(FFA)),butwereabsentinolderadults.Inaddition,therewasan

age‐relateddecreaseinfunctionalconnectivitybetweenFFAandrightinferior

frontaljunction(IFJ),middlefrontalgyrus(MFG),andintraparietalsulcus(IPS),

whichwascorrelatedwiththemagnitudeofFFApre‐stimulusactivitymodulation

onlyinyoungeradults.Moreover,whileFFAconnectivitywithIFJpredicted

enhancedexpectation‐relatedWMperformance,andFFAconnectivitywiththeMFG

predictedLTMimprovementsinyoungeradults,thesecorrelationswith

performancewerenotevidentinolderadults.Thesedatasuggestthatnormalaging

isaccompaniedbyfunctionalchangesinfrontal‐parietaltop‐downnetworksthat

mediateexpectation‐relatedprocesses,whichareassociatedwithimpaired

utilizationofpredictiveinformationtoguideoptimalWMandLTMperformance.

POSTERSESSION‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

MilagrosCopara

BrainNetworksUnderlyingSpatialandTemporalSourceRepresentation

MilagrosCopara,EveIsham,Wei‐chunWang,AndyYonelinas,ArneEkstrom

UCDavis

Episodicmemoriespermeateourlivesanddefinepastevents.Timeandspaceare

criticalandintegralcomponentsofepisodicmemory;withouttheseessential

elements,wewouldnotbeabletodiscernourmemoriesfromoneanother.The

neuralcontributionstothesecomponents,however,remainunclear.Spatialand

temporalsourcememoryhavebeenexaminedinseveralparadigms,butnoneof

themtodatehaveeffectivelybeenabletoisolateeachofthesecomponentsinorder

totestthemindependentlyandsimultaneously.Inourparadigm,weaccomplishthis

byhavingsubjectsnavigateavirtualenvironmentwithvariousstores,located

equidistanttothecenter,wheretheyencodeboththespatiallocationsandtheorder

inwhichtheyencountereachstore.Toexploretheenvironment,thesubjectsare

instructedtodeliverapassengertoeachstoreinaspecificorder,thusexperiencing

uniquespatialroutesandtemporalorder.Duringfunctionalmagneticresonance

imaging(fMRI)usinga32channelcoilwitha3TSiemensTrioTotalimagingmatrix

(TIM)scanner,subjectsretrievedspatialandtemporalsourceinformationrelevant

tothetask.Subjectsfirstsawareferencestoreandanswerediftheysawthatstore

previously.Subjectswerethenaskedtocomparetwootherstores’spatiallocations

(inthespatialblock)ortemporaldistances(inthetemporalblock)tothereference

storeandanswerwhichstoreiscloserspatiallyortemporally.Imagingbrain

activitywithechoplanarimaging(EPI)sequences2x2x2mm,weregisteredour

individualactivationsontotheanatomicalimages(wholebrain1x1x1mmMPRAGE

sequences)todeterminetheareaactiveduringthetask.Weconductedbothregion

ofinterestanalysesbasedonexpectedareasofbrainactivation(hippocampus,

parahipopcampalcortex,andprefrontalcortex)andwholebraincontrasts.Our

resultsshowthatthereisequalhippocampalactivityforbothspatialandtemporal

tasks,althoughhippocampalactivitydiddiscriminatebetweencorrectandincorrect

sourceretrieval.Furthermore,theprefrontalcortexwasuniquelyactivatedforthe

temporaltask,andtheparahippocampalcortexwasuniquelyactivatedforthe

spatialtask.Theseresultsindicatethatwhilespatialandtemporalinformationmay

beprocessedbyindependentnetworksinthebrain,theremaybeaconvergenceof

thesetwocomponentsofsourcememoryinthehippocampus.Thisconvergence

mayresultinacommonsourcerepresentationthatcontributessignificantlytothe

encodingandretrievalofourepisodicmemories.

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KyleLyman

Neuralcorrelatesofresponseinhibitionafter­effects

JoaquinAAnguera1,KyleLyman2,andAdamGazzaley11.TheUniversityofCaliforniaSanFrancisco,SanFrancisco,California

2.TheOhioStateUniversity,Columbus,Ohio

Motorinhibitionhasbeenstudiedextensivelyinrecentyearsthroughtheuseofthe

stop‐signalparadigm(LoganandCowan1984).Severalstop‐signalstudieshave

reportedalongerreactiontimetoa'GO'signalwhentheimmediatelypreceding

trialinvolvedthepresentationofastopsignal(RiegerandGauggel1999).Inthe

presentstudy,weexaminedtheunderlyingneuralcorrelatesofthisbehavioral

after‐effect,hypothesizingthatthesemeasuresmaybeindicativeof

disengagement/inhibitionfromapreviouslyprimedstate.Alternatively,thiseffect

mayreflectswitchingbetween'GO'and'Stop'tasksets.19youngadultparticipants

(18‐30yrs)performed6blocks(100trials/block)ofthestop‐signaltask,withstop‐

signalsappearingon25%oftrials.EEGrecordingsweretakensimultaneously.The

ERPeffectsrevealednoconditionalmodulationofvisualattention(P1/N170)or

conflict(N2)attheelectrodeofinterest,PO7(determinedbygreatestmodulation

amongstallconditions).ERSPtheta(4‐7Hz)andalpha(8‐12Hz)bandswere

examinedattheFCZelectrodeforeachconditionbetween‐3000and1000msec.

TherewasadifferenceinERSPsynchronizationduringtheinter‐trialinterval

followingastop‐signaltrial,inlinewithneurophysiologicalindicesofstrategy

development(Smith,MeEvoy,Gevins1999)thatpositfrontalmidlinethetarhythm

isassociatedwiththemaintenanceofdistincttaskmentalsets.Thesefindings

suggestthatbehavioralafter‐effectsmaybetterreflecttheconsciousdecision

betweentasksets('GO'and'Stop'),ratherthanafunctionofpersistentinhibition‐

relatedresources.

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JoshuaPhillips

RuleMaintenanceEffectsonEpisodicMemoryinSchizophrenia

Phillips,J.,Ragland,J.D.,RanganathC.,RamsayI.S.,HeusserA.,Niendam,T.A.,Yoon

J.H.,SolomonM.,CarterC.S.,UCDavis

Background:Individualswithschizophreniahavedifficultymaintainingrulestoguide

behavior,leadingtoerrorsoninhibitiontasksliketheStroop.Thecurrentstudytests

whetherthesesamerulemaintenanceproblemsmighthelpexplainepisodicmemory

deficitsinpatientswithschizophrenia.

Methods:SixteenhealthycontrolsandseventeenpatientsunderwentfMRIwhileencoding

wordsduring2conditions:

1)“Rule”–aliving/nonlivingjudgmentwasmadewhenthecoloroftargetwordsmatched

thecolorofasurroundingbox.A“skip”responsewasmadewhencolorofnon‐target

wordsdidnotmatch.

2)“No‐Rule”–living/nonlivingjudgmentsweremadeforallwords.Subjectswere

instructedtoencodeonlyitemsforwhichtheymadealiving/non‐livingjudgment.A

subsequentrecognitiontaskwasperformedoutsidethescannerrequiringdiscrimination

oftargetandnon‐targetitemsfromnewitems.

Results:Therewerenogroupdifferencesinencodingtaskperformance,withbothgroups

performingabove90%.Subsequentmemoryanalysisrevealedaninteraction;patients

wereuinimpairedintheNo‐Rulecondition,butwereimpairedintheirabilitytofacilitate

memoryfortargetsandinhibitmemoryfornon‐targetsintheRulecondition.Thiswas

accompaniedbyreducedprefrontalcortex(PFC)activationinpatientsduringtheRule

conditioninrostrolateralandanteriorcingulateregions.

Conclusions:Theseresultsprovidepreliminaryevidencethatepisodicmemory

impairmentsinschizophreniaaremostprominentwhenthelearningcontextrequires

memoryfacilitationforsomeitemsandinhibitionforothers.Thisappearsdueto

dysfunctioninareasrequiredforhigher‐orderrulerepresentation(rostrolateralPFC)and

conflictdetection(anteriorcingulate).

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

LukeJenkins

Accuratetemporalcontextmemoryisassociatedwithgreatermultivoxel

patternchangeintheprefrontalcortex

LukeJenkins,UCDavis

Oneofthedefiningfeaturesofepisodicmemoryistheabilitytorecallaneventinits

appropriatetemporalcontext.InthisfMRIexperiment,wesoughttodetermine

whethertrial‐to‐trialchangeinthepatternofactivityacrossvoxelsduringan

encodingtaskwouldpredicttemporalaccuracyatrecall.Participantswerescanned

during72trialsofaserialorderworkingmemorytaskinvolvingpicturesof

commonobjects.Followingscanning,theywereshownoneobjectfromeachofthe

encodingtrialsandaskedtoindicateapproximatelywhenduringthecourseofthe

experimentthisobjecthadbeenencounteredbymarkingitspositiononan

horizontalline.AstandardGLManalysisrevealeddelay‐periodactivityinthe

ventro‐,dorso‐,androstrolateralprefrontalcortex(RLPFC)thatpredictedaccuracy

onthesubsequentmemorytask.WethenusedtheseclustersasROIsinaseparate

multivariateanalysis.WithineachROI,multivoxelactivationpatternswere

recordedfromthedelayperiodofeachtrial,andameasureofmultivariatedistance

(Euclidean)wascalculatedbetweeneachtrialandtheimmediatelyadjacenttrials

(lags+/‐1,2,3,4).Repeated‐measuresANOVArevealedasignificanteffectoflagin

theRLPFCROI,suchthattheactivationpatternforagiventrialwasmoresimilarto

thepatternatlag+/‐1thanat+/‐4.Moreover,thedistancebetweenagiventrial

anditsadjacentneighborsineitherdirectionwasgreaterforaccuratethanfor

inaccuratetrials.Thefactthattrial‐to‐trialpatterndistinctivenesswithintheRLPFC

predictedsubsequenttemporalaccuracyconstitutesnovelevidenceforthe

importanceofthisregionintemporalcontextencoding.

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DanielleKing

Leftparietalactivationduringretrievalofperceivedandimaginedevents

DanielleKing,UCSantaBarbara

Theparietalold/neweffectisthecommonfindingthatregionsinleftposterior

parietalcortex(PPC)aremoreactiveduringrecognitionofoldthannewitems.

Explanationsforthiseffectincludetheoutputbufferhypothesis,proposingthat

activityreflectstherepresentationofcontextualdetailsassociatedwithanepisodic

memory,andthemnemonicaccumulatorhypothesis,suggestingthatactivity

reflectsthesubjectiveperceptionthatinformationisold(Wagner,Shannon,Kahn,&

Buckner,2005).Wescannedsubjectsinareality‐monitoringexperimenttotest

whetheracontextualdetailorsubjectiveperceptionaccountcouldbetterexplain

activationinleftPPC.Subjectsperceivedandimaginedobjectsinresponsetocue

words,andwerethengivenasurprisememorytest,wheretheysawoldandnew

words,andjudgedwhethereachwaspreviouslyperceived,imagined,ornew.

Studieshaveshownthatmemoriesfromperceptionarecharacterizedbygreater

contextualdetailsthanmemoriesfromimagination(Johnson,Hashtroudi,&

Lindsay,1993).Therefore,wepredictedthatifleftPPCrepresentscontextualdetails

ofepisodicmemories,thanactivationshouldbegreaterduringretrievalof

perceivedthanimaginedevents.Further,theparietalold/neweffectshouldbemore

robustduringretrievalofmemoriesfromperceptionthanimagination.Incontrast,

ifactivityreflectsthesubjectiveperceptionthatinformationisold,thanactivity

shouldbesimilaracrossconditions.However,onnewtrials,activityshouldbe

greaterforitemsmistakenlyjudgedasold(falsealarms)thanthoseaccurately

recognizedasnew(CRs).Theresultsstronglysupportthepredictionsofanepisodic

bufferaccount.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

TheodoreZanto

Spatio­temporaldynamicsinworkingmemoryformotiondirection:AnfMRI

guidedEEG/TMSstudy

TheodoreZanto,UCSF

Recentstudieshaveindicatedthataregionwithintheprefrontalcortex(PFC),the

inferiorfrontaljunction(IFJ),isengagedinencodingvisualfeaturesintoworking

memory,yetthenecessityofthisregionandthetimingunderlyingfrontal‐posterior

communicationremainsunclear.Here,weutilizetranscranialmagneticstimulation

(TMS)inconjunctionwithelectroencephalography(EEG)toexplorethenetwork

dynamicsbetweenthePFCandvisualassociationcortex(VAC)duringamemory‐

for‐directiontask.Theexperimentconsistedoftwovisits:aninitialfunctional

magneticresonanceimaging(fMRI)sessiontoidentifyTMStargetsandasecond

visitwhereparticipantsperformedthesametaskasthefirstsession,butEEGwas

recordedwhilesinglepulseTMSwasapplied.Eachtrialconsistedoftwomotion

stimuliwitha2000msinter‐stimulus‐intervalafterwhichparticipantswere

requiredtoindicatewithabuttonpresswhetherthetwodirectionsofmotionwere

thesameordifferent.ThreeTMStargetswereidentifiedbasedontheindividual

participant'sfMRIdata:IFJ(PFC),V5(VAC)andvertex(control).Duringthesecond

session,eachofthethreeTMStargetsiteswerestimulatedduringseparateblocks.A

singleTMSpulsewasappliedeither‐100,‐50,0,50,100or150mspost‐stimulus

oneonset(i.e.thestimulustoberemembered).Behavioralandneuralmeasures

convergetoshowthatPFC‐VACcommunicationareengagedinananticipatory

fashionandremainsonlineduringstimuluspresentation,whichoptimizesencoding

motiondirectionintoworkingmemory.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

Jin­ChenYang

DefaultModeNetworkDysfunctioninMildAlzheimer’sDisease:Evidencefrom

anIncidentalVerbalLearningTask

Jin‐ChenYangandJohnOlichney,UCDavis

Explorationontherelationshipofmemoryanddefaultnetworkfunction

impairmentmayshedlightonthemechanismofattentionandshort‐termmemory

interaction.InthepresentfunctionalMRI(fMRI)study,awordrepetitionparadigm

wasemployedtoinvestigatethedefaultmodenetworkactivationanddeactivation

inNormalElderly(NE)andmildAlzheimer’sdisease(AD)patients.Resultsshowed

that,intherightinferiorparietallobule(IPL),NEhaddeactivationresponsefornew

wordandgreateractivationforoldwords,whereastheopposite(Newword>Old

word)responsepatternwasobservedinAD.Whileinleftposteriorcingulatecortex

(PCC),NEshowedaNew>OldpatternbutADgrouphadnoNew>Oldeffectsin

thisarea.Severalotherregionsindefaultmodenetworkwerealsoexamined.The

defaultmodenetworkdysfunctioninmildADandtheimplicationtomemoryand

attentionsystemswerediscussed.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

SandraMineyev

Eyemovementssuggestbindingofspatialandtemporalinformationinepisodic

memory

SandraMineyev1,EveA.Isham1,2,NicholasDiQuattro2,JoyJ.Geng2,ArneD.Ekstrom11. CenterforNeuroscience,UniversityofCalifornia,Davis,CA..

2. CenterforMindandBrain,UniversityofCalifornia,Davis,CA.

Twocriticalcomponentsofepisodicmemoryarespatialandtemporalinformation,

whichdefinethe“where”and“when”aneventoccurred.Giventhatbothspatial

andtemporalinformationareintegralpartsofepisodicmemory,itisunclear

whetherthesetwocomponentsareencodedandretrievedtogetherasasingle

entity(bound)orwhethertheyrelyonseparatemechanisms.Thecurrentstudy

investigatedthesequestionsbyexaminingeyemovementsduringaspatialor

temporalmemoryretrievaltask.Thirteenparticipantsnavigatedthroughavirtual

environmentandwereaskedtomakedeliveriestoelevenstoresinaspecificorder.

Afterthenavigationtask,theparticipantsweretestedfortheirspatialandtemporal

memorywhilewerecordedtheireyemovements.Duringthisretrievaltask,the

participantswereaskedtomakeeitheraspatialortemporaljudgmentabout;the

spatialjudgmenttaskpromptedtheparticipantstochoosewhichofthetwostores

wascloserindistancetothereferencestorewhilethetemporaljudgmenttask

promptedtheparticipantstochoosewhichofthetwostorechoiceswascloserin

deliveryordertothereferencestore.Withinagiventrial,theparticipantswere

presentedwitha10x10gridonthecomputermonitortorepresentthemapofthe

environmentnavigated.An“X”markedthelocationofthereferencestoreonthe

gridmap.Theamountofeyemovementdwelltimewascalculatedasthe

percentageoftimespentlookingattheunmarkedregionsofinterestonthegrid

whichrepresentedthetwostorechoices.Ifspatialandtemporalinformationare

strictlyboundasasingleentitywithintheepisodicmemory,theamountofeye

movementdwelltimeshouldbethesameduringthespatialandtemporaltasks.

However,ifspatialandtemporalcomponentsoperateindependently,thedwelltime

shouldreflectthesedifferences.Ourpreliminarydata(N=13)suggestthattheeye

movementdwelltimeduringspatialandtemporaltasksarenotsignificantly

differentfromoneanother,F(1,12)=1.995,p=.18,h2=.14.Thisfindingsuggeststhe

possibilityofbindingoftemporalandspatialinformationwithinepisodicmemory.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

LauraLibby

Definingrestingstatenetworkswithinthehumanhippocampalformationusing

high­resolutionimagingandfunctionalconnectivity

*L.A.LIBBY1,A.D.EKSTROM2,C.RANGANATH2;1Psychology,Univ.ofCalifornia,Davis,CA;2PsychologyandCtr.forNeuroscience,Univ.of

California‐Davis,Davis,CA

Numerousstudiessupporttheimportanceofthehumanhippocampalformationin

episodicmemory,withdifferenthippocampalsubregionscontributingtodiscrete

memoryprocesses.Anatomicalstudiesinrodentssuggestthatperirhinalcortex

(PRC)andparahippocampalcortex(PHC)providestronginputintothe

hippocampus,andhumanneuroimagingandlesionworksuggeststhatthesetwo

areasplaydistinctrolesintheinputofitemandcontextinformationforrecognition

memorywithinthehippocampus.However,howPHCandPRCinteractwithhuman

hippocampalsubregionsremainsunclear.Asafirststeptowardaddressingthis

issue,weusedhigh‐resolutionfMRI(hr‐fMRI)duringresttoexamineintrinsic

functionalconnectivitybetweenanatomically‐definedPRCandPHCandother

hippocampalsubregions.Echo‐planarimagingwasusedtoobtainaseriesofimages

perpendiculartothelongaxisofthehippocampusata1.5mm^2in‐plane

resolutionandregisteredtoahigh‐resolutionT2‐weightedstructuralimage(0.4

mm^2in‐planeresolution).WedemarcatedregionsofinterestforCA1,

CA23/dentategyrus(DG),subiculum,PRC,PHC,entorhinalcortex(ERC),and

fusiformcortex.Basedontheseanatomically‐definedregionsofinterest,we

extractedBOLDtimecoursesforfunctionalconnectivityanalysis.Preliminary

analysesusingPRCandPHCseedregionsrevealedadistributedrestingnetworkof

functionallyconnectedregionswithinthehippocampalregion.Inparticular,we

notedsignificantfunctionalconnectivitybetweenPRCandPHCseedsandERC,

subiculum,CA1,andCA23/DG.Together,thesedatasuggestconvergencewith

previousanatomicalmappingofthehippocampalformationinanimalmodels.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

BenHutchinson

Effectsofdecisionframingonepisodicretrieval

BenHutchinson,StanfordUniversity

Whileneuroimagingstudiesofepisodicretrievalhaveconsistentlyrevealed

activationinposteriorparietalcortex(PPC),thereremainsmuchdebateaboutthe

functionalrolesofdorsalandventralPPCregionsinmemory.Aparallelliterature

implicatesPPCinprocessesengagedduringperceptualdecision‐making,suggesting

similarprocessesmayalsocontributetoepisodicretrieval.ThecurrentfMRIstudy

manipulateddecisioncriteriainordertodisentanglePPCresponsesassociatedwith

mnemonicevidencefromresponsesassociatedwithdecisionprocesses.

Participantsincidentallyencodedvisuallypresentedwords,andweresubsequently

scannedwhileperformingtworecognitionmemorytests.Inthefirsttest,a

between‐subjectinstructionalmanipulationvariedwhetherparticipantsmadea1‐5

pointconfidenceratingaboutitemnoveltyoritemfamiliarity.Inthesecondtest,

participantsperformedastandardold/newrecognitiontask(making

old/new/unsureresponses).PPCregionsshowinggreateractivationduringhitsvs.

correctrejections(i.e.,“old/neweffects”)onthislattertestwereinterrogatedfor

sensitivitytoinstructionalframingintheconfidence‐ratingtest.Theresultssuggest

thatold/newsensitiveregionsintheinferiorparietallobule,neartheintraparietal

sulcus,areinsensitivetodecisioncriteria.Additionalanalysessuggestthataregion

withinthesuperiorparietallobuletracksthedecisionuncertainty,whereasaregion

ofangulargyrusdemonstratesaninversepattern.Thesefindingsunderscorethat

multipleinteractingprocesseswithinPPCcontributetoepisodicretrieval.

TALKSESSION2

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

HuiZhang

Thetaactivityrelatedtoutilizationofcoherentspatialrepresentations

HuiZhang,AndrewWatrous,CharanRanganath,ArneEkstrom,UCDavis

Humansreferencetolandmarksinordertoarriveatunseenspatiallocations.While

previousworksuggeststheimportanceoffrontalthetaoscillationsinobject

recognitionandcategorization(Weidemannetal.,2009),thereisnodirectevidence

regardinghowlow‐frequencyoscillationsrelatetoviewingandreferencing

differentkindsoflandmarksduringnavigation.Toaddressthisissue,subjectsfirst

encodedlocationsofstoresfromamap‐likeperspectivewithreferencetoa

centrallylocatedlandmarkandarandomlylocatedstore.Inthetestphase,during

whichwerecordedneuralactivityfromthescalpwithelectroencephalography

(EEG)recordings,subjectsactivelynavigatedtotargetstoresusinglandmarksfrom

afirst‐personperspectiveinfourrandomlyinterspersedconditions.Thesewere:a

visibletargetcondition(navigatingtothevisibletargetstore),alandmarkcondition

(navigatingtoahiddenstoreusingthelandmark),astore‐referencecondition

(navigatingtoahiddenstoreusinganotherstoreasthelandmark),andarandomly

locatedtargetcondition(searchingforarandomly‐locatedstore).Previousdata

showedthattheposteriorsuperiorparietalcortexisrecruitedduringsurvey

representationencoding(SheltonandGabrieli,2002)suggestingthatthisregion

mayalsoparticipateinsurveyretrieval.Thus,wehypothesizedincreasesintheta

oscillatorypoweroverparietalcortexrelatedtolandmarkretrieval.Wefirst

focusedonthetimewhenthelandmarksfellintothefieldofview.Wefoundgreater

thetapowerinboththelandmarkandvisibletargetconditioncomparedtothe

randomlylocatedtargetstoreconditionatparietalcorticalelectrodeswhensubjects

viewedlandmarkstolocalizethehiddentargets.Wealsofoundhigherthetapower

whenanotherstoreservedasalandmarkinthestore‐referenceconditionthan

whenreferencingtothelandmark.Thesedatatogethersupporttheroleoftheta

oscillationsinlandmarkprocessing,particularlywhensubjectsneededtointerpret

thespatialrelationsofobjectsrelativetothelandmarkinanovelfashion.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

MaheenAdamsom

Reducedhippocampalactivityduringencodingincognitivelynormaladults

carryingtheAPOEε4allele

MaheenM.Adamson,PhD1,2,J.BenjaminHutchinson3,AmyShelton,PhD4,

AnthonyWagner,PhD3,&JoyL.Taylor,PhD1,2

1DepartmentofVeteransAffairsandSierra‐PacificMIRECC,PaloAlto,California,

2DepartmentofPsychiatryandBehavioralSciences,

StanfordUniversitySchoolofMedicine,Stanford,California

3PsychologyDepartment,StanfordUniversity,Stanford,California

4DepartmentofPsychologicalandBrainSciences,JohnHopkinsUniversity,Baltimore,Maryland

Apolipoprotein(APOE)ε4‐relateddifferencesinmemoryperformancehavebeen

detectedbeforeage65.Thehippocampusandthesurroundingmedialtemporal

lobe(MTL)structuresarethefirstsiteaffectedbyAlzheimer’sDisease(AD)andthe

MTListheseatofepisodicandvisuospatialmemory.APOEε4‐relateddifferencesin

thesebrainstructuresarenotconsistentineithercross‐sectionalorlongitudinal

studies.Thereisincreasingevidencethatthebrainactivityatfixationmaybe

differentinAPOEε4carrierscomparedtonon‐carriers.Inthisstudy,cognitively

normalAPOEε4carriersandnon‐carriersengageinaperspective‐dependent

learningtask(Shelton&Gabrieli,2002)previouslyshowntoactivateMTL

structuresinolderparticipants(Borghesanietal.,2008).Alow‐level,visually

engagingdot‐controltaskwasusedforcomparisontoprovidenon‐MTL‐based

activity,inadditiontofixation.Routevs.surveyperspectiveswerenotdifferentin

ε4carrierscomparedtonon‐carriers(p>.1)andtherewasnoGenotypex

Perspectiveinteraction,(p>.1).Whentheencodingofthetwoperspectiveswas

contrastedagainstthedot‐controltasktheencoding‐relatedactivationwas

significantlyhigherthanthedot‐control(p<.001)andtherewasaGenotypexTask

interaction(p<.05).Noε4‐relateddifferencesinthehippocampuswerefound

whenencodingduringthetwoperspectivetaskswascomparedwithfixation.The

resultsofthisstudyhaveimplicationsforfMRIstudiesthatinvestigatethetask‐

positivenetwork(TPN)anddefault‐modenetwork(DMN)inAPOEε4carriersto

helpevaluateADriskintheotherwisecognitivelynormalpopulation.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

Liang­TienHsieh

EEGcorrelatesofitemandtemporalorderinformationinworkingmemory

Liang‐TienHsieh1,ArneD.Ekstrom1,2,CharanRanganath1,21DepartmentofPsychology,UCDavis;2CenterforNeuroscience,UCDavis

Theabilitytomaintaintemporalorderinformationinworkingmemory(WM)is

crucialinourdailylife.Forinstance,whendialingarecentlylearnedphonenumber,

onemustmaintainnotonlytherelevantitems(i.e.,thedigits),butalsotheir

temporalorder(i.e.,thesequenceofdigits).Resultsfromscalp

electroencephalography(EEG)andintracranialEEG(iEEG)studieshaveindicated

thatoscillatoryactivityinthetheta(4‐8Hz)andalpha(9‐13Hz)bandsiscorrelated

withWMmaintenance.However,littleisknownaboutthedifferencesinoscillatory

activitybetweenthemaintenanceofitemandtemporalorderinformationinWM.

Onechallengeinaddressingthisquestionisthatdifferencesintaskdifficultyusually

complicatetheinterpretationofbrainactivitydifferencesbetweentestsofWMfor

iteminformationandtestsofWMfororderinformation.Accordingly,inthepresent

study,weattemptedtocomparetheneuralcorrelatesofmaintenanceofitemand

orderinformationwhilecontrollingforoveralltaskdifficulty.WerecordedEEG

whileparticipantscompletedtwotypesofWMtrials:ITEMtrialsandORDERtrials.

Oneachtrial,participantsseeaninstructionword(either“ITEM”or“ORDER”),

followedbyfoursequentiallypresentedfractals,andthenatestdisplay.OnORDER

trials,thetestdisplayconsistedoftwofractalsfromtheprevioussequenceinwhich

participantswereaskedtoidentifywhichfractalcameearlierinthesequence.On

ITEMtrials,thetestdisplayconsistedofonepreviouslypresentedfractaland

anothervisuallysimilarfoilfractalthatwasnotinthesequencewithparticipants

identifyingtheoldfractalonITEMtrials.Behavioralresultsrevealedthataccuracy

andreactiontimesweresimilarforITEMandORDERtrials,suggestingthattask

difficultywasmatchedbetweenthetwoconditions.PreliminaryscalpEEGanalyses

indicatethatoscillatoryactivity,particularlyinthethetaband,wasmodulatedby

maintenanceofitemandorderinformation.Wehavealsoadaptedthetaskfor

testingwithpatientswhohaveimplantedelectrodesforseizuremonitoring.We

obtainedsimilarresultstoourscalpEEGwithonepatient,confirmingthattheta

oscillationsplayanimportantroleinmaintainingtemporalinformationinWM.

Together,thesedataunderscoretheimportanceofcoordinatedneuralactivityin

thetheta‐bandforcorrectlymaintainingtheorderofinformationinarecently

learnedlist.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

RickAddante

Pre­stimulusthetaactivitypredictsrecollectionduringretrievaltasks

RickAddante,UCDavis

Researchontheneuralbasisofhumanmemoryhasproceededfromtheassumption

thatmemoryretrievalisdrivenbyincomingstimulithatactascuestoelicit

recoveryofpastexperiences.However,recentresearchsuggeststhatthe

neurocognitivestatethatthebrainisinpriortostimuluspresentationcanalsoplay

acriticalroleindetermininghoworganismsrespondtopresentedstimuli(Fox&

Raichle,2007;Mazaherietal.2009).Ongoingbrainactivityhasbeenrelatedto

subsequentpsychophysical,motor,andmemoryperformance(Buzaki,2006;

Raichle,2009).However,whetherhigherlevelcognitivefunctionssuchasmemory

retrievalareinfluencedbyendogenousneuralactivityisunknown.Recentworkhas

shownthatneuralactivitypriortoencodingastimuluscaninfluencesubsequent

memoryperformance(Guderianet.al.2009;ParkandRugg,2010),thoughtherole

ofongoingbrainactivitypriortomemoryretrievalremainsunexplored.Wetested

episodicretrievalofbothitemandsourcememorywhilerecordingEEGin17

humansubjects,andfoundthatpre‐stimulusthetapowerpriortoaretrievalcue

selectivelypredictssuccessfulrecollection.Post‐stimulusthetaactivitywasalso

enhancedforaccuratememoryperformance,andwasfurthershowntobe

modulatedbythepre‐stimulustheta.Bothpreandpost‐stimuluseffectswere

correlatedwithbehavioralperformanceofsourceaccuracy,challengingtraditional

stimulus‐responsemodelsofbrainfunction.Thesefindingsdemonstratethatneural

processesoccurringpriortostimulusonsetplayanessentialroleinhowbrain

processesachievesuccessfulmemoryretrieval.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

MiramAly

RecollectionandFamiliarityinLong­TermMemory,Perception,andEverything

inBetween

MariamAlyandAndrewP.Yonelinas

UCDavis

Weinvestigatedwhetherprocessesanalogoustorecollectionandfamiliarityin

long‐termrecognitionmemoryoperateinperceptionandshort‐termmemorytasks.

Thedualprocesssignaldetectionmodelwasusedtoestimaterecollectionand

familiarityfromobservedreceiveroperatingcharacteristics(ROCs).Themodelfit

theperceptionandshort‐termmemoryROCswell,butincontrasttolong‐term

memory,recollectionsupportedthedetectionof'newness',not'oldness'.Themodel

wastestedbymanipulatingwhetherdiscreteorglobalsimilarityinformationwas

moreuseful.Discretecomparedtoglobalchangesincreasedrecollectionand

decreasedfamiliarity.Insightsaboutrecollectionandfamiliarityfromthese

experimentsledtopredictionsabouthowtheseprocessesshouldoperateinlong‐

termmemory,whichweretestedusinganovel'memorychangedetection'task.We

foundthatparticipantsnolongerrecollected'oldness'butratherrecollected

'newness'initemrecognition.Thus,thesametheoreticalframeworkisusefulin

integratingphenomenaacrossbothmemoryandperceptionparadigms.

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

JoshuaKoen

Theeffectsoftemporalcontiguityontheneuralcorrelatessupporting

recognitionmemoryfornovelcrossmodalassociations

JoshuaDKoen,UCDavis

Ithasbeenwellestablishedthatthehippocampusiscriticalinformingnovel

associationsthatcanbelaterrecollected,whereasregionsinthesurrounding

medialtemporallobe(MTL)areinvolvedinencodingiteminformationthat

supportsfamiliarity‐basedmemorydiscriminations.However,recentevidence

suggeststhatpatientswithfocalhippocampaldamagecanexhibitrelatively

preservedassociativerecognitionunderconditionsthatpromoteunitization(i.e.,

encodingtheconstituentsofanassociationasasingleitem),whichsuggeststhat

familiaritymaycontributetoassociativerecognition.Evidenceinfavorofthese

unitizationeffectshascomefromstudiesofwordpairs,anditisunknownifthese

effectsgeneralizetononverbalmaterials.Toexaminethisissue,participants

underwentfMRIscanningwhileencodingpairsoffractalsandabstractsoundsthat

werepresentedsimultaneouslyorsequentially(e.g.,temporallydiscontinuous),

whichwasfollowedbyanassociativerecognitiontest.Itwaspredictedthatthe

abilityofparticipantstounitizethefractal‐soundpairsshouldbedisruptedwhen

theconstituentsofthepairsarepresentedinatemporallydiscontinuousmanner.

Thus,theabilityoffamiliarityandtheanteriorMTLtocontributetoassociative

recognitionshouldbereducedundersuchconditions.Aspredicted,estimatesof

familiarityweresignificantlyhigherforpairspresentedsimultaneouslythanpairs

presentedsequentially.Moreover,preliminaryanalysesofthefMRIdatarevealthat

activityinmultipleMTLsubregionswascorrelatedwithsubsequentassociative

recognition.Furtheranalyseswillassesstheextenttowhichactivityinmultiple

MTLsubregionsdifferentiallysupportassociativerecognitioninthesimultaneous

andsequentialconditions.

TALKSESSION3

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

MatthiasGruber

Encoding­relatedbrainactivitybeforeanevent:Theroleofstrategiccontrol

MatthiasGruber,UCDavis

A new development in our understanding of human long‐term memory is that

effective memory formation relies on brain activity just before an event. It is

unknown whether such prestimulus activity is under voluntary control or a

reflectionofrandomfluctuationsovertime.InExperiment1,electricalbrainactivity

was recorded while healthy adults memorized series of words. Each word was

precededbyacue,whichindicatedthemonetaryrewardthatwouldbereceivedif

the following word was later remembered. Brain activity before word onset

predicted later memory of a word. Crucially, this was only observed when the

incentivetomemorizeawordwashigh.Thissuggeststhatengagingbrainactivity

that benefits the encoding of an upcoming event is under voluntary control. In

Experiment 2, we addressed whether encoding‐related prestimulus activity

dependsonthedegreetowhichneuralresourcesareallocatedtoanencodingtask.

Participants had to memorize each word and additionally make an alphabetic

judgmentoneachword.Again,activitybeforewordonsetpredicted latermemory

performance. Interestingly, this effectvariedaccording toan individual’s accuracy

on the alphabetic task. Encoding‐related prestimulus effects were larger when

individuals made more mistakes on the alphabetic task. These results suggest a

trade‐off between processes that support encoding versus alphabetic judgments.

Together,thetwoexperimentsimplythatencoding‐relatedbrainactivitybeforean

upcomingeventreflectsaresource‐dependentpreparatoryprocesswhichisunder

strategic control. This opens up new avenues to improve memory, especially in

clinicalandeducationalsettings.

­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­

RachelDiana

Encodingitem,context,andrelationalinformation:fMRIadaptationinthe

medialtemporallobes

RachelA.Diana,AndrewP.Yonelinas,&CharanRanganath

UCDavis

Themedialtemporallobesarecriticalforencodingofepisodiclong‐termmemories,

howeverthespecificfunctionsofmedialtemporallobesubregionsremainunclear.

TheBindingofItemandContext(BIC)modelofmedialtemporallobefunction

proposesthattheperirhinalcortexprocessesiteminformation,the

parahippocampalcortexprocessescontextinformation,andthehippocampus

processestheconjunctionofitemandcontextinformationinarelationalbinding.

WeusedanfMRIadaptationparadigmtotestthepredictionsoftheBICmodel

duringencodingofepisodicmemories.Adpatationstudiesrelyonthegeneral

findingthatrepetitionofinformationleadstoreducedactivationinbrainareasthat

processtherepeatedinformation.Thus,repetitionofiteminformation(inthiscase,

concretenouns,e.g."HAMMER"),contextinformation(uniquesemanticencoding

questions,e.g."Couldyoubalancethisitemonyournose?),andrelationalbindings

ofitemandcontextinformation(thejointprocessingofanounandanencoding

question,e.g."Ican'tbalanceahammeronmynose.")shouldleadtoreduced

activationinmedialtemporallobesubregionsthatprocesseachtypeofinformation.

WefoundfMRIadaptationeffectsinperirhinalcortex,parahippocampalcortex,and

thehippocampuswithrepeatedencodingofitem,context,anditem‐context

bindingselicitingdifferentamountsofadaptationineachmedialtemporallobe

subregion.

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ValerieCarr

High­resolutioninvestigationofpatternseparationinthemedialtemporallobe

usingarapidfMR­adaptationapproach

ValerieA.Carr,SerraE.Favila,andAnthonyD.Wagner

Tensionisthoughttoexistwithinthemedialtemporallobe(MTL)whenevents

shareoverlappingfeatures,suchthatsomesubfieldsreadilyencodeagiveneventas

distinctfrompreviously‐experiencedevents(e.g.,patternseparation),whereas

othersgeneralizeacrosssimilarevents.Inanefforttobettercharacterizeputative

functionalheterogeneityamongMTLsubfields,twostudieswereconducted

examiningthemannerinwhichsubfieldsrespondtoparametricmanipulationsof

eitheritemorrelationalsimilarity.Inbothcases,participantswerescannedusing

high‐resolutionfMRIandarapidadaptationparadigminwhichtrialsbeganwith

presentationofanovelstimulus,followedbyastimulusvaryinginsimilaritytothe

novelstimulus.Wehypothesizedthat(a)whentwostimuliwereidentical,

adaptationwouldbeseenacrossallMTLsubfields,and(b)critically,differentlevels

ofadaptationwouldappearacrosssubfieldsasafunctionofstimulussimilarity.

Analyseswereperformedintwoways:(1)participant’simageswerekeptinnative

space,andactivitywasextractedfromanatomicalregionsofinterest(ROI),(2)

participant’simageswereregisteredintoagrouptemplateusinganROI‐alignment

technique(ROI‐AL)toallowforgroup‐levelvoxel‐basedanalyses.Resultsreveal

regionaladaptationdifferencesbetweenthehippocampusandMTLcorticesinboth

studies,aswellassubregionaldifferenceswithinthehippocampussuchthat

CA/dentategyrusplaystheclearestroleinpatternseparation.