PhDdefense ofLorrainePerronnetSeptember 7th,2017
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Directors:AnatoleLécuyer ChristianBarillot
Advisors:MaureenClercandFabienLotte
Combining EEG fMRIforNeurofeedback
Neurofeedback (NF)
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Introduction>
Motor rehabilitation ofstrokepatients
Definition: “Neurofeedback is a type of biofeedback in which neural activity is measured,and a visual, an auditory or another representation of this activity is presented to theparticipant in real time to facilitate self-regulation of the putative neural substrates thatunderlie a specific behaviour or pathology” [Sitaram et al. 2016]
Neurofeedback (NF)
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AcquisitionBrainactivity ismonitored
Pre-processingSignalis cleanedfrom nonneuronal
components
Feature extractionAfeature ofinterest
is extracted
FeedbacktranslationThefeature is fed backtothesubject viaavisual,
auditory ortactilefeedback
Subject self-regulationSubject perceives feedback
andadapt his mentalstrategy tocontrolit
REAL-TIMECLOSEDLOOP
Introduction>
NFmodalities
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EEG
MEGfNIRS
fMRI
Temporalresolution (s)
Spatialresolution(m
m)
111111
0.01 0.1 1 10
10
1EEG+fMRI
Highspatial(mm)andhightemporal(ms)resolution
Introduction>
Problem andmotivation
Limitedefficiency/efficacy ofunimodal NFapproaches
Designnovel NFapproaches combining EEGandfMRI that couldbe moreeffectivethan unimodal approaches
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Introduction>
5)Feedback
Challengesofcombined EEG/fMRI forNF
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EEG
fMRI
1)Neurovascularcoupling
6)Real-timeprocessing
4)Dataintegration
2)Experimentaldesign
3)fMRI featureselection
3)EEGfeatureselection
Introduction>
Thesis objectives
1. Identify critical methodological aspectsthat differ between EEG-nfandfMRI-nf (Related works>EEG-nf vsfMRI-nf)
2. ExplorehowtocombineEEG andfMRI forNF(Related works>Contribution1)
3. Develop anexperimental EEG/fMRI NFplatform (Contribution2)4. Evaluate added valueofbimodalEEG-fMRI-nf overunimodal NF
(Contribution3)5. Proposeandevaluate strategies torepresent EEG andfMRI
simultaneously (Contribution4)
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Introduction>
Outline
• Related works• Contribution1(methodo.):Taxonomy ofEEG/fMRI NFstudies
• Contribution2(techno.):EEG/fMRI NFplatform• Contribution3(study):Unimodal vsbimodalNF• Contribution4(methodo.+study):Towards integrated feedback• Conclusion• Perspectives
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EEG-nf vsfMRI-nf
EEG-nf fMRI-nf
NFsignal • Amplitudeofspecificfrequencybandsatone,twoelectrodesites
• Slowcorticalpotentials[Rockstroh etal.1990]
• Z-scoreNF[Thatcher etal.,1998]• Source-based(Loreta-NF,BSS-NF)
[Cannonet al.2009,Whiteetal.2014]
• AveragepercentsignalchangeinROI• Differentialsignalbetweentworegions• MVPA, Effectiveconnectivity[Sulzer etal.,2013]
Task design Block,continuous/self-paced BlockTask duration Flexible: usually2-5minutes,fewseconds
forMI, tensofminutesfordeepstateNF15- 45seconds
Nbofsessions 20- 40 5- 10
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Related works >
Cross-modalevaluation /validation
• fMRI before/after EEG-nf• Plasticity induced byasinglealphadownEEG-NFsession[Rosetal.,2012]• After 30minutesofNF,increase ofconnectivity within
regions ofthesalience networkinvolved inintrinsicalertness (dACC)
• Passive fMRI during EEG-nf• fMRI signatureofMI-based EEG-nf [Zich etal.,2015]
• EEGandBOLDcontralateral activity is correlated• EEGandBOLDlateralization patternsarenotalways correlated
• Passive EEG during fMRI-nf• Correlation between amygdala BOLDactivity and
frontalEEGasymmetry during fMRI-nf inMDDpatients [Zotev etal.,2016]• Average frontalalphaasymmetry changessignificantly
correlated with theamygdala BOLDlaterality
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RealBCIilliterates
PseudoBCIilliterates
Related works >
fMRI-informed EEG-nfEEG finger-print (EFP){electrode,frequency}offMRI deep regional activation[Meir-Hasson etal.,2014],[Linetal.2017]:time-frequencydecomposition ofEEG,ridge regression
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CommonEFPmodel(valid across subjects andsessions)[Meir-Hasson etal.,2016]:oneclassclassification,hierarchicalclustering algorithm applied totheestimated EFPmodels’coefficients
Related works >
EEG-fMRI-nf[Zotev etal.,2013]
• Methods• Participants:6healthy subjects• Task:emotional self-regulation• EEG feature:frontalhigh-beta(21-30Hz)asymmetry• fMRI feature:left amygdala
• Authors hypothesized that:EEG-fMRI-nf >EEG-nf |fMRI-nf• Limitations
• 2separate feedbackgauges• Noevaluation against unimodal NF
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Related works >
Outline
• Related works• Contribution1(methodo.):Taxonomy ofEEG/fMRI NFstudies
• Contribution2(techno.):EEG/fMRI NFplatform• Contribution3(study):Unimodal vsbimodalNF• Contribution4(methodo.+study):Towards integrated feedback• Conclusion• Perspectives
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Systemdescription(1)
• Goal• Develop aplatform abletodosimultaneous acquisitionandreal-timeprocessing ofEEG andfMRI toprovide unimodal andbimodalNF
• Challenges• Multimodal• Real-timeperformance• Artifacts (gradient,pulse,helium pump,ventilation)• Novel approach,nocomprehensive solutionavailable
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Contribution2:EEG/fMRI NFplatform >
Systemdescription(2)
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NFBUnit(InhouseMatlab/C/C++/Javacode)
• Real-timeparallel EEG andfMRI processing(pre-processing,feature extraction)
• NFcalculation• Communicationwith subject (feedback,
cues andinstructions)• Experiment/protocol control• Timingcontrolandsynchronization
EEGsubsystem
fMRI subsystem
64ch.MR-safe BrainProducts EEGcap
3TSiemensVerio
Fiber delay (~80ms)+displayrefresh (1-17ms)
EEGupdate<200ms
fMRI update≤250ms
Subject
Contribution2:EEG/fMRI NFplatform >
Published in:MMano,ALécuyer,EBannier, LPerronnet,SNoorzadeh,CBarillot (2017). HowtobuildahybridneurofeedbackplatformcombiningEEGandfMRI. FrontiersinNeuroscience,11, 140.
My role
• State-of-the-artandspecifications• Issuedetection andresolution• Recruiting volunteers• Runningtheexperiments andanalyzing thedata
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Contribution2:EEG/fMRI NFplatform >
Outline
• Related works• Contribution1(methodo.):Taxonomy ofEEG/fMRI NFstudies
• Contribution2(techno.):EEG/fMRI NFplatform• Contribution3(study):Unimodal vsbimodalNF• Contribution4(methodo.+study):Towards integrated feedback• Conclusion• Perspectives
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• Goal: evaluate theadded valueofEEG-fMRI-nf compared tounimodal EEG-nf andfMRI-nf• Participants:10healthy subjects(28+/- 5.7y,2females)• Design:within-subject• Collected data:EEG +fMRI• Task:kinesthetic motor-imagery (kMI)oftherighthandunder unimodal/bimodalNFconditions• Evaluationcriteria:
• EEG andfMRI activationlevels• fMRI activationmaps• Questionnaires
Goalandmethods
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Contribution3:Unimodal vsbimodalNF>
Experimental protocol
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1session
MotorlocalizerRight-handclenching
NF1Right-handkMI
NF2Right-handkMI
NF3Right-handkMI
ConditionsA,BandCarepseudo-randomly ordered foreach subject
Rest Task(10×)
MI_preRight-handkMI
MI_postRight-handkMI
fMRI ROI
20s 20s
Contribution3:Unimodal vsbimodalNF>
Features
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EEG feature:
• Electrodes:C1andC2• Frequency band:µ(8-12Hz)• Baseline:from previous rest block• NFrate:8Hz
fMRI feature:
• ROI:9×9×3boxoverleft andrightM1[Chiew etal.,2012]
• Baseline:from previous rest block• NFrate:0.5Hz(=TR)
Features:laterality indicesbetween left andrightmotor area
M1
Contribution3:Unimodal vsbimodalNF>
Experimental conditions
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+
ConditionA:EEG-NFEEG
fMRI
+
ConditionB:fMRI-NFEEG
fMRI
+
ConditionC:EEG-fMRI-NFEEG
fMRI
Contribution3:Unimodal vsbimodalNF>
Unimodal Bimodal
Hypotheses
HypothesesH1:Generalized NFeffectH2:DirectNFeffectH3:Compromiseeffect
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˃˃
Level ofNF-related fMRI activityLevel ofNF-related EEGactivity
≤≤ ≤≤(H3)
(H3)
(H2)(H2)
(H2)
(H2)
˃˃
˃˃
˃˃
>>0 (H1)
>>0(H1) >>0(H1)
>>0 (H1)
Contribution3:Unimodal vsbimodalNF>
>>0(H1)>>0(H1)
Demo
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Contribution3:Unimodal vsbimodalNF>
Unimodal Bimodal
Results >BOLDactivationmaps
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• Stronger,bigger andmorewidespread activationsduring EEG-fMRI-NF=>higher level ofengagementorhigher level ofself-regulation ?
fMRI-NF EEG-fMRI-NFEEG-NF
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Contribution3:Unimodal vsbimodalNF>
Unimodal Bimodal
(TASK>REST;p>0.05FWEcorrected;k>10voxels)
Results >NFperformance(online)
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• EEG laterality significant inNF2,fMRI laterality significant inNF1• Highinterandintrasubject variability• Loss ofperformanceononlinefMRI laterality between NF1andNF3• Nosignificant difference between NFconditions• Laterality indicesmight havebeentoo hardtoregulate inonesession
Contribution3:Unimodal vsbimodalNF>
EEG laterality (byNFcond.) EEG laterality (byrun order) fMRI laterality (byrun order)fMRI laterality (byNFcond.)
A:EEG-nfB:fMRI-nfC:EEG-fMRI-nf
Results >NFperformance(posthoc)
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• EEG andBOLD activity significantly higher during NFthan during MI_pre =>H1• BOLD activity significantly higher during EEG-fMRI-nf than during EEG-nf =>H2• Nosignificant difference onEEG between NFconditions
Contribution3:Unimodal vsbimodalNF>
EEG ERDonCSPfiltereddata(byNFcond.)
EEG ERDonCSPfiltereddata(byrun order)
fMRI PSCinposthoc ROI(byrun order)
fMRI PSCinposthoc ROI(byNFcond.)
A:EEG-nfB:fMRI-nfC:EEG-fMRI-nf
Results >Questionnaire
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fMRI was easier tocontrolthan EEG 6/10EEG was easier tocontrolthan fMRI 3/10EEG andfMRI were asdifficult tocontrol 1/10Same attentiongiven toboth feedbackdimensions 8/10Moreattentiongiven tothe dimensionthat washardertocontrol
2/10
During EEG-fMRI-NF:
Contribution3:Unimodal vsbimodalNF>
+
EEG
fMRI
Discussion
• Need further studies toreinforce our results andevaluate therest ofthehypotheses• Oppositetendency ofonlineEEG andfMRI features• Onemodality can be regulated attheexpense oftheother
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Contribution3:Unimodal vsbimodalNF>
Summary
• We conducted astudy that compared forthefirsttimeEEG-fMRI-nf toEEG-nf andfMRI-nf• Mainresults• Participantsareabletoregulate hemodynamic andelectrophysiologicalactivity simultaneously during unimodal andbimodalMI-based NF
• BOLDactivity higher during EEG-fMRI-nf than during EEG-nf
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Contribution3:Unimodal vsbimodalNF>
Published in:LPerronnet,ALécuyer,MMano,FLotte,MClerc,CBarillot (2017).UnimodalversusbimodalEEG-fMRIneurofeedbackofamotorimagerytask. FrontiersinHumanNeuroscience.
Outline
• Related works• Contribution1(methodo):Taxonomy ofEEG/fMRI NFstudies
• Contribution2(techno):EEG/fMRI NFplatform• Contribution3(study):Unimodal vsbimodalNF• Contribution4(methodo +study):Towards integrated feedback• Conclusion• Perspectives
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FeedbackdesignforEEG-fMRI-nf
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• InEEG-fMRI-nf,greater amount ofinformationwith nontrivialrelationship=>Howtorepresent theEEGandfMRI features simultaneously?
• Problem ofseparate feedbacks• 2feedbacks,2targets ~2concurrentregulation tasks• Highcognitiveload• Does notallow todefine aNFtarget characterized bythepairoffeatures
• Concept:we proposetointegrate theEEGandfMRI features inasinglefeedback
Contribution4:Towards integrated feedback>
[Zotev etal.,2013]
ToappearUnderreview
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Contribution4:Towards integrated feedback>
Outline
• Related works• Contribution1(methodo.):Taxonomy ofEEG/fMRI NFstudies
• Contribution2(techno.):EEG/fMRI NFplatform• Contribution3(study):Unimodal vsbimodalNF• Contribution4(methodo.+study):Towards integrated feedback• Conclusion• Perspectives
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Conclusion• Goal:designnovel NFapproaches combining EEGandfMRI
• Contribution1(methodo.):Taxonomy ofEEG/fMRI NFstudies• Thetaxonomy showsthere aremany ways ofcombining EEGandfMRI forNFpurpose• We havefocused onEEG-fMRI-nf:simultaneous onlineuseofEEGandfMRI asNFsignal• Thereis still roomleft forimprovements andforthedevelopment ofnewapproaches
• Contribution2(techno.):EEG/fMRI NFplatform• We havedeveloped anefficientplatform that allowed ustotestandevaluate methods forbimodalNF• Itwill continuetobe improved andused forexperiments
• Contribution3(study):Unimodal vsbimodalNF• We havedemonstrated that during anMItask bimodalEEG-fMRI-nf triggersstronger BOLDactivationsthan unimodal EEG-nf
• Contribution4(methodo.+study):Towards integrated feedback• We haveintroduced theconceptofintegrated feedbackforEEG-fMRI-nf (onefeedback/onetarget)• We haveproposed two integrated feedbackstrategies,a2Danda1D• The1Dfeedbackis easier tocontrolonasinglesession• The2DfeedbacktriggersmoreactivationintherightSPLandencouragessubjects toexplorementalstrategies
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Conclusion
Perspectives
• Experimental design• Mixedprotocols• Investigate other modality couples(EEG+fNIRS ?)
• Feedback• Investigate other integrated feedbackparadigms• Multi-sensory bimodalfeedback
• Applications• Upcoming clinical tests(depression,stroke)
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Perspectives
Publications• Journal
• L Perronnet, A Lécuyer, M Mano, F Lotte, M Clerc, C Barillot (2017). Learning 2-in-1: towards integrated EEG-fMRI-NF. [Review in progress].• L Perronnet, A Lécuyer, M Mano, F Lotte, M Clerc, C Barillot (2017). Unimodal versus bimodal EEG-fMRI neurofeedback of a motor imagery
task. Frontiers in Human Neuroscience.• L Perronnet, A Lécuyer, F Lotte, M Clerc, C Barillot (2016). Entraîner son cerveau avec le neurofeedback / Brain training with neurofeedback. Les
interfaces cerveau-ordinateur 1 : Fondements et méthods / Brain-Computer Interfaces 1: Foundations and Methods. pp. 277-292, (Wiley-ISTE).• M Mano, A Lécuyer, E Bannier, L Perronnet, S Noorzadeh, C Barillot (2017). How to build a hybrid neurofeedback platform combining EEG and
fMRI. Frontiers in Neuroscience, 11, 140.
• Conferences• L Perronnet, A Lécuyer, F Lotte, M Clerc, C Barillot. Neurofeedback unimodal ou bimodal ? Intérêt de l’EEG et de l’IRMf. 2ème journée nationale
sur le neurofeedback, ESPCI Paris, France, January 2017. [Invited talk]• L Perronnet, A Lécuyer, M Mano, E Bannier, F Lotte, M Clerc, C Barillot. EEG-fMRI neurofeedback of a motor imagery task. 22nd Annual Meeting
of the Organization for Human Brain Mapping (OHBM 2016), Palexpo, Geneva, Switzerland, June 2016. [Poster]• M Mano, E Bannier, L Perronnet, A Lécuyer, C Barillot. Design of an Experimental Platform for Hybrid EEG-fMRI Neurofeedback Studies. 22nd
Annual Meeting of the Organization for Human Brain Mapping (OHBM 2016), Geneva Palexpo, Switzerland, June 2016. [Poster]• L Perronnet, Anatole Lécuyer, Marsel Mano, Elise Bannier, Fabien Lotte, Maureen Clerc, & Christian Barillot. HEMISFER: Hybrid EegMrI and
Simultaneous neuro-FEedback for brain Rehabilitation. 1ère journée nationale sur le neurofeedback, ICM, Paris, France, January 2016. [Poster]• E Bannier, M Mano, S Robert, I Corouge, L Perronnet, J Lindgren, A Lécuyer, C Barillot (2015). On the feasibility and specificity of simultaneous
EEG and ASL MRI at 3T. Proceedings of ISMRM. [Abstract]
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• AnatoleandChristian• Allthemembers ofthejury• Volunteers• Marsel• Elise,Isabelle• Angélique,Armelle,Nathalie• VisagesandHybrid members• TheMRtechnicians• Doctors• Family• Friends• Shiatsuteacher• Theperson present byhis absence• Andallofyou !
SpecialTHANKSto
https://lowpe.github.io/lorraineperronnet/