食品质量检测专业英文论文_图文

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CerebralCortexOctober2005;15:1602--1608

doi:10.1093/cercor/bhi038

AdvanceAccesspublicationFebruary9,2005

PicturesofAppetizingFoodsActivate

GustatoryCorticesforTasteandReward

Increasingresearchindicatesthatconceptsarerepresentedas

distributedcircuitsofpropertyinformationacrossthebrain’s

modality-specifirentstudyexaminesthedistributed

representationofanimportantbutunder-exploredcategory,foods.

Participantsviewedpicturesofappetizingfoods(alongwithpictures

oflocationsforcomparison)edto

locationpictures,foodpicturesactivatedtherightinsula/operculum

andtheleftorbitofrontalcortex,bothgustatoryprocessingareas.

Foodpicturesalsoactivatedregionsofvisualcortexthatrepresent

ertheseareascontributetoadistributedneural

ydoesthiscircuit

becomeactiveduringthetastingofactualfoods,italsobecomes

processofpattern

completion,foodpicturesactivategustatoryregionsofthecircuit

tentwith

theoriesthatgroundknowledgeinthemodalities,theseinferences

ariseasreenactmentsofmodality-specificprocessing.

Keywords:concepts,fMRI,insula/operculum,knowledge,orbitofrontal

cortex

Introduction

Howareconceptsforeverydayobjectsrepresentedinthe

brain?Basedonaccumulatinglesionandneuroimagingevi-

dence,anobjectconceptisrepresentedasadistributedcircuit

ofpropertyrepresentationsacrossthebrain’smodality-specific

areas(Martin,2001;MartinandChao,2001;Thompson-Schill,

2003).Onencounteringaphysicalobject,relevantmodalities

bjectis

processed,associationareaspartiallycapturepropertyinforma-

tiononthesemodalities,sothatthisinformationcanlaterbe

reactivatedduringconceptualprocessing,whentheobjectis

absent(DamasioandDamasio,1994;SimmonsandBarsalou,

2003).Althoughtheseconceptualreenactmentsshareimport-

antcommonaltieswithmentalimagery,therearealsoimportant

imagerytypicallyresultsfromdeliberate

attemptstoconstructconsciousvividimagesinworking

rast,theperceptualreenactmentsthatunderlie

conceptualprocessingoftenappeartolieoutsideawareness,

resultinginsteadfromrelativelyautomaticandimplicitpro-

aryinterest,thesereenactmentsoccurin

responsestowordsandothersymbols,andplaycentralroles

intherepresentationofconceptualknowledge(Barsalou,1999,

2003a,b;Barsalouetal.,2003a,b).

Thecategoryoftoolsillustratesthedistributionofproperty

representationsacrossmodality-specifi

peopleuseahammer,adistributedsetofbrainareasbecomes

activetorepresentthehammer’sproperties,includingitsvisual

form(ventraloccipitotemporalcortex),thephysicalactions

Óhtsreserved.

Forpermissions,pleasee-mail:sions@

mmons

1

,AlexMartin

2

ou

1

1

DepartmentofPsychology,

2

EmoryUniversity,Atlanta,

GA30322,USAandCognitiveNeuropsychologySection,

LaboratoryofBrainandCognition,NationalInstituteof

MentalHealth,Bethesda,MD,USA

usedtomanipulateit(ventralpremotorcortexandintraparietal

sulcus),andthevisualmotionthatresults(middletemporal

gyrus)(Beauchampetal.,2002;Chaoetal.,1999;Chaoand

Martin,2000;Damasioetal.,2001;Graftonetal.,1997;Handy

etal.,2003;Johnson-Frey,2004;Martinetal.,1995;Peranietal.,

1995).Asjustdescribed,thebrain’sassociationareascapture

thisdistributedsetofmodality-specificstatesforlaterconcep-

equentoccasions,whennohammersare

present,reenactmentsofthesestatesrepresenthammerscon-

ceptually(languagecomprehensionandthought).

Intheexperimentreportedhere,weexploredthedistributed

onstitute

acentralcategoryforhumans,notonlyinperceptionandaction,

butinhighercognition(RossandMurphy,1999).Previous

researchonfoodconceptshasaddressedthevisualpropertiesof

fruitsandvegetables,relativetothevisualpropertiesofother

objectcategories(McRaeandCree,2002).Here,wefocus

insteadonthetastesofhigh-caloric,high-fatprocessedfoods,

suchascheeseburgersandcookies(seeFig.1).Wefocusontaste

propertiesbecausethetastesoffoodsareatleastasimportantas

sonprocessedfoodsbecause

theyarecentraltothemoderndietandbecausetheyare

associatedwithstronggustatoryandappetitiveresponsesthat

underliehowpeopleselectandconsumethem.

Ifadistributedcircuitofpropertyinformationrepresents

foodknowledge,thenviewingafoodpictureshouldnotonly

activatebrainareasthatrepresentvisualpropertiesofthe

picturedfood,butshouldalsoactivatebrainareasthatrepresent

howthefoodislikelytotasteandhowrewardingitwouldbeto

epartofthedistributedcircuitbecomesactiveby

viewingthepicture,theremaindershouldbecomeactivevia

theconceptualinferenceprocessofpatterncompletionacross

hecentralrolethatsuchinferencesplayin

normalfoodselectionandconsumption,itisessentialto

rmore,giventhe

extensivenessofeatingdisorders,obesityandotherfood-

relatedproblems,itisimportanttounderstandhowpeople

generatetasteandrewardinferencestothebroadarrayoffood

representationsavailableinmodernculture.

Wepresentedpicturesoffoodandnon-foodentities(loca-

tionpictures)tosubjectsundergoingevent-relatedfMRIand

predictedthatadistributedcircuitofbrainareaswouldbecome

activetorepresentthevisualandgustatorypropertiesofthe

ingthevisualpropertiesoffoods,alarge

literaturedemonstratesthatventraltemporalregionsunderlie

therepresentationofobjects’visualformproperties(Ishaietal.,

1999,2000).Thus,weexpectedregionsoftheinferiortemporal

andfusiformgyritorespondtothedistinctivevisualproperties

ously,locationpicturesshould

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esoflocation,food,andscrambledimagestimuli.

activateparahippocampalgyrus,giventhatthisregionresponds

tothevisual-spatialpropertiescharacteristicofbuildingsand

landmarks(Aguirreetal.,1998;EpsteinandKanwisher,1998;

Epsteinetal.,1999).

Mostimportantly,thecurrentstudyattemptedtodemonstrate

thatpicturesofvisualobjects,inthiscasefoods,canproduce

istributedaccountofconceptrepresen-

tationiscorrect,thenmultiplemodality-specificregionsshould

onlyshouldvisualareasbecomeactivetorepresentafood’s

uniquevisualproperties,gustatoryareasshouldbecomeactive

opleaccessknowledge

forapicturedfood,aninferenceisproducedabouthowittastes.

Eventhoughpeoplearenotactuallytastingthefood,their

gustatorysystembecomesactivetorepresentthisinference.

Specifically,wepredictedthatsimplyviewingpicturesof

appetizingfoods(relativetolocations)shouldactivatetwo

brainregionsthatcommonlyrespondtoactualtastestimuliin

psychophysicalneuroimagingstudies(Francisetal.,1999;de

Araujoetal.,2003a,b;O’Dohertyetal.,2001b).Thefirstarea,

aregionintheinsula/operculum,isknowntorepresenthow

foodsactuallytaste(Rollsetal.,1988;RollsandScott,2003;

Scottetal.,1986).Thesecondarea,aregioninorbitofrontal

cortex(OFC),isknowntorepresenttherewardvaluesoftastes

(Gottfriedetal.,2003;Rollsetal.,1989).Herewedemonstrate

thatsimplyviewingpicturesofprocessedfoodsactivatesboth

brainregionsinmuchthesamewaythattastestimulantsdoin

psychophysicalstudies.

MaterialsandMethods

Subjects

Nineright-handed,native-English-speakingvolunteersfromtheEmory

Universitycommunityparticipatedinthescanningstudy(sixfemaleand

threemale;agerange,18--45years).Allparticipantscompletedahealth

questionnairepriortoscanningandnoneoftheparticipantsindicated

rdancewithprotocols

prescribedbyEmoryUniversity’sInstitutionalReviewBoard,allpartici-

pantsreadandsignedaninformedconsentdocumentdescribingthe

proceduresandpossiblerisks.

Sixteennative-English-speakingvolunteersfromtheEmorycommu-

nityparticipatedinthestimulusselectionstudy(tenfemaleandsix

male;age19--46years).Noneofthesevolunteersparticipatedinthe

theimagingparticipants,all

participantsreadandsignedaninformedconsentdocumentdescribing

theproceduresandpossiblerisksinaccordancewithprotocols

prescribedbyEmoryUniversity’sInstitutionalReviewBoard.

ExperimentalDesign

Beforebeginningthebrainimagingphaseofthestudy,32typesoffoods

foods(burger,spaghetti,cookie,etc.)inthelistwerechosen

addition,onlyprocessedfoodsthatarerelativelyhighinfatandcalories

house,mall,school,etc.)inthelistwerechosenbecausetheyareall

typesofplacesthatparticipantsinthestudymightvisitfrequently.

Thefoodsandlocationswereequatedforfamiliaritybyhaving

volunteers(noneofwhomparticipatedinthebrainimagingexperi-

ment)providefamiliarityratingsforthe35typesoflocations,and32

sweremadeona1--7scale,with1indicatingthat

atypeoffoodorlocationwascompletelyunfamiliarand7indicating

ntheseratings,15foodand15

locationtypeswereselectedsuchthatnoreliablefamiliaritydifferences

nsixandtenpictures

foreachtypeoffoodandlocationwerethencollected.

Agroupof16participantsviewedall259picturesandratedeachfor

swere

madeona1--7scale,with1indicatingthatapicturewasnotatalltypical

eachtypeoffoodorlocation,thethreemosttypicalpictureswere

selectedforuseintheimagingstudy,thusyieldingatotalof90picture

stimuli(45foods,45locations)hefoodand

locationpicturesdepictednon-uniqueentitiesthatwouldnotbe

y,23location

picturesand22foodpictureswererandomlyselectedtocreate

phase-scrambledimagesthatwerepresentedduringscanningasfiller

items(seeFig.1).

Duringscanning,participantsviewedfood,locationandscrambled

hpicture,participantsusedaresponsepadtoprovide

yes/nojudgmentsastowhetheritwasthesameordifferentasthe

tureswerepresentedinthecenterofthe

persedamongpicturepresentationswere

variable(‘jittered’)interstimulusintervals(mean

=

5.7s,range

=

2--20s)

thatwereincludedtooptimizeestimationoftheevent-relatedfMRI

theseinterstimulusintervals,participantssawafix-

ipantswere

instructedthatwhentheysawthefixationcrosstheyshouldcontinue

attendingtothescreenandprepareforthenextpicturepresentation.

Priortobeginningdatacollection,participantsperformedanabbre-

viatedpracticeruntoinsurethattheyunderstoodthetaskinstructions.

allistsfor

each

run,npicture

presentationsfromeachcategorywerenovelpictures,whileone

picturewasrepeatedtomaintaintheparticipants’attentiontothe

rwords,onelocationpicture

the

threescanningruns,eachsubjectsawthreefoodpicturerepetitionsand

tsweretoldinadvancethat

gthisandgiven

thattherepeatedstimulioccurredinfrequently,thistaskrequires

subjectstopaycloseattentiontoeachpicturepresentationtoinsure

afromtherepetition

trialsineachrunwerenotanalyzedgiventhattheywereonlyincluded

tswere

highlyaccurateatrepetitiondetection(Meancorrect

=

98.8%,SD

=

0.94).Each5min8srunconsistedof4min48softherepetition

detectiontask,followedbyanadditional20srestperiod.

CerebralCortexOctober2005,V15N10

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