talk session 1 - memory lab · 2019. 8. 29. · talk session 1 jesse rissman striatal contributions...
TRANSCRIPT
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).
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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.
‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
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.