FMRI of language output : conceptual priming and practice

103 Pages·2000·4 MB·English

by  Sadek, Joseph Richard

FMRIOFLANGUAGEOUTPUT:CONCEPTUALPRIMINGANDPRACTICE
By
JOSEPHR.SADEK
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
2000
Copyright2000
by
JosephR.Sadek
Thisdissertationisdedicatedtomyparents,MargaretandGeorgeSadek.
ACKNOWLEDGMENTS
Iwouldliketoacknowledgemychairperson,BruceCrosson,andallthosewho
workinhislaboratorywhohavecontributedtothisproject. ThisincludesM.Allison
Cato,LeezaMaron,ChrisLoftisDidemGokcay,EdwardAuerbach,KaundinyaS.
Gopinath,DavidSoltysik,LeahGriffin,RimaAsh,andHopeBenefield. Specialthanks
gotoRichardBriggs,whoprovideddetailedrevisionsofthisdissertationandphysics
expertise,andtoRussellBauer,whosecognitivepsychologyexpertisewasessential.
ThankstoLeslieGonzalezRothiforkeeninsightintoimportantissues,andtoDawn
Bowersforconsistentsupport. KathleenHaalandisacknowledgedforhelpful
interpretiveadvice. TheNationalFoundationforFunctionalBrainImagingin
Albuquerque,NewMexico,andtheirsystemsanalysis,RobertChrisner,are
acknowledgedfortheuseoftheircomputersystems,withoutwhichtheanalysiswould
nothavebeenpossible. TimConwayisrecognizedforsacrificingtimewithhisfamilyto
helpmeprepareforthedefensemeeting. SpecialthanksalsogotoSarahKortenkamp,
NatalyaZelikovsky,MarinaUnrod,andJohannaEsquerreforsupportthroughoutthe
dissertationprocess. Finally,thankstothosestudents(T.C,A.C,L.M.,C.L,andD.
S.)whoattendedthedefense.
IV
TABLEOFCONTENTS
page
ACKNOWLEDGMENTS iv
LISTOFTABLES vii
LISTOFFIGURES viii
ABSTRACT x
LANGUAGEANDPRIMING 1
CognitiveNeuropsychologicalModelofLanguage 2
Priming:DefinitionandReview 4
CharacteristicsofPriming 6
TransferAppropriateProcessing 8
PerceptualPriming 10
H
ConceptualPriming
PriminginCategoryExemplarGeneration 12
MechanismsofConceptualandOutputSystemsPriming 14
THENEURALBASISOFPRIMING 18
EvidenceRegardingAmnesia 18
EvidenceRegardingFunctionalNeuroimaging 20
PerceptualSystems 20
SemanticandOutputSystems 21
AnatomicSubstratesofConceptualPriming 24
Lateralfrontalcortex 24
Medialfrontalcortex 26
PRACTICE: DEFINITIONANDREVIEW 30
HYPOTHESES 33
EXPERPMENT1 36
Methods 37
Participants 37
Materials 37
Design 38
ExperimentalTasks 39
Procedure 40
Analyses 42
Results 43
PrimingResults 43
PracticeResults 44
Discussion 46
Priming 46
Practice 4/
EXPERIMENT2 48
Methods 48
Participants 48
Materials 50
Procedure 51
FMRIDataCollection 53
DataAnalysis 54
Results 60
Priming 60
Practice 64
GENERALDISCUSSION 69
Priming 69
SmallEffectSize 71
PrimingofAtypicalExemplars 72
OtherMethodologicalDifferences 73
Practice 76
LISTOFREFERENCES 81
BIOGRAPHICALSKETCH 89
VI
LISTOFTABLES
Table Page
Table1. ProportionofCorrectWordsthatWerePrimedandAverageNumberofWords
ProducedforPrimedandUnprimedCEG 44
Table2. PercentCorrectonRecognitionProbeComparedtoActualPerformance 44
Table3. AverageNumberofWordsProducedforEachCategoryacrosstheThree
PracticeTrialsofCategoryExemplarGeneration 45
Table4. AverageDisplacement(mm)androtation(degrees)after3-DimensionalImage
RegistrationAcrossAllImagesandSlices 55
Table5. MagnitudeofPriming(%targetsinprimedcategoriesminus%targetsin
unprimedcategories)for11ParticipantsWhoShowedPriming 60
Table6. RegionsofActivationforthePrimedandUnprimedCEG 62
Table7. RegionsofDeactivationforPrimedandUnprimedCEG 63
Table8. AverageVolumesofActivation(inmicroliters)inMedialFrontalCortexfor
PrimedSubjects 64
Table9. RegionsofSignificantDifferenceamongLevelsofPractice: ANOVAResults..66
Table10. AverageVolumesofActivation(inmicroliters)inMedialFrontalCortexfor
LevelsofPractice 66
vn
LISTOFFIGURES
Figure Pag&
Figure1. CognitiveneuropsychologicalmodeloflanguageproposedbyEllisandYoung
(1988) 3
Figure2. Cognitivemechanismofword-cuedassociation 15
Figure3. Cognitivemechanismofcategoryexemplargenerationpriming. Darkarrows
representprocessesalsoengagedbystudytaskinFigure3andrepresent
primedprocesses 16
Figure4. Averagenumberofsharedexemplarsbetweenpracticetrials,n=11 46
Figure5. Medial(x=5)andlateral(x=45)leftfrontalactivationduringgenerationof
unprimed(toprow)andprimed(bottomrow)categories.Redandyellow
representtask-relatedactivationatp<.001andp<.0001respectively. Dark
andlightbluerepresentactivationoccurringduringtherestperiodatp<.001
andp<.0001respectively. Thegreencrosshairsarelocatedattheyandz
origin(0,0) 61
Figure6. Practiceeffectsastestingbywithin-subjectsANOVA. Redrepresentsp<
.001,whileyellowrepresentsp<.0005. Activationrepresentsregionsthat
differbetweenthethreelevelsofpractice 65
Figure7. Posthoct-testscomparingpracticelevel1vs.level2andlevel1vs.level3.
Bothred(p<.001)andyellow(p<.0001)representhigheraveragesignalin
levels2and3comparedtolevel1 67
Figure8. Post-hoct-testscomparingthemeanofeachlevelofpracticetoahypothetical
meanof (noactivationatthatlevel). Noticethattherearemanyregionsof
commonactivation. Comparethecircledregionstoeachotherandtothe
regionsofdifferenceinFigures4and3. Thisregionrepresentsthemain
effectsoftheANOVAdepictedinFigure3andindicatesthatthemaineffect
isduetoalowerlevelofactivationinPracticelevel1 68
Figure9. HypotheticalBOLDresponsetoprimingofhighlytypicalversuslesstypical
categoryexemplars. Lesstypicalexemplarsmayrequiremoreenergyfor
retrievalthanhighlytypicalexemplarsingeneral,withoutpriming,and
Vlll
thereforeresultindifferencesinbaselineactivationlevelsbetweenaccessing
highlytypicalvs.lesstypicalexemplars.(Bvs.C). Thelackofpriming
effectsinthepresentstudymaybeduetothepossibilitythatprimingofless
typicalcategoryexemplarsresultedinsimilarMRIsignalcomparedto
unprimedhighlytypicalexemplar(Cvs.D). Energydemands(presumably
influencingBOLDresponse)betweenretrievalofprimedatypicalexemplars
andunprimedtypicalexemplarsisthereforesimilarandnotdetectedinthe
presentstudy '3
IX
AbstractofDissertationPresentedtotheGraduateSchool
oftheUniversityofFloridainPartialFulfillmentofthe
RequirementsfortheDegreeofDoctorofPhilosophy
FMRIOFLANGUAGEOUTPUT:CONCEPTUALPRrMTNGANDPRACTICE
By
JosephR.Sadek
August2000
Chairman: BruceCrosson,Ph.D.
MajorDepartment: ClinicalandHealthPsychology
Primingisaformofimplicitmemorythatresultsinfacilitationofbehavior
withoutconsciousawareness. Primingisfrequentlyintactinpatientswhoareotherwise
unabletoconsciouslyrecallrecentlylearnedinformation. Primingofsinglewordscan
occurbyemphasizingthephysicalaspectsofthewordsorbyemphasizingthesemantic
aspectsofthewords,(perceptualandconceptualpriming). Thetheoryoftransfer
appropriateprocessingsuggeststhatprimingisduetotheoverlapincognitiveprocesses
betweenthestudyphaseandthetestphaseofprimingexperiments. Recentfunctional
neuroimagingstudieshavesuggestedthatprimingmaycauseareductioninneuralenergy
needsrelatedtofacilitatedaccesstoprimedinformation. Perceptualprimingis
associatedwithactivationreductioninareasofcortexknowntobeinvolvedinperceptual
processing,whileconceptualprimingresultsinactivationreductioninareasofcortex
thoughttobeinvolvedinsemanticprocessing.
Twoexperimentsweredesignedtoexplorewhetherconceptualprimingof
categoryexemplargenerationcanresultinactivationreductionsinleftlateralandleft