SPM 2002SPM 2002

Experimental DesignExperimental DesignSPM 2002SPM 2002

Experimental DesignExperimental Design

Daniel GlaserDaniel Glaser

Institute of Cognitive Neuroscience, UCLInstitute of Cognitive Neuroscience, UCL

Slides from:Slides from:

Rik Henson, Christian Buchel, Karl Friston,Rik Henson, Christian Buchel, Karl Friston,

Chris Frith, Cathy Price,Ray DolanChris Frith, Cathy Price,Ray Dolan

The Wellcome Department of Cognitive Neurology, UCLThe Wellcome Department of Cognitive Neurology, UCL

London UK http//:www.fil.ion.ucl.ac.uk/spmLondon UK http//:www.fil.ion.ucl.ac.uk/spm

Data transformationsData transformations

RealignmentRealignment SmoothingSmoothing

NormalisationNormalisation

General linear modelGeneral linear model

Statistical parametric map (SPM)Statistical parametric map (SPM)Image time-seriesImage time-series

Parameter estimatesParameter estimates

Design matrixDesign matrix

TemplateTemplate

KernelKernel

Gaussian Gaussian field theoryfield theory

p <0.05p <0.05

StatisticalStatisticalinferenceinference

SPM{T}SPM{T}

speed

isoluminant stimuli (even)

isochromatic stimuli (odd)

V5V5

+

+

StimuliStimuli

A taxonomy of designA taxonomy of designA taxonomy of designA taxonomy of design

• Categorical designsCategorical designsSubtraction Subtraction - Pure insertion and cognitive subtraction- Pure insertion and cognitive subtraction

- Differential event-related fMRI - Differential event-related fMRI

Conjunction Conjunction - Testing multiple hypotheses- Testing multiple hypotheses

• Parametric designsParametric designsLinear Linear - Cognitive components and dimensions- Cognitive components and dimensions

NonlinearNonlinear - Polynomial expansions and neurometric functions- Polynomial expansions and neurometric functions

- Nonlinear event-related fMRI- Nonlinear event-related fMRI

• Factorial designsFactorial designsCategoricalCategorical - Additive factors and pure insertion- Additive factors and pure insertion

- Psychopharmacological designs- Psychopharmacological designs

- Adaptation, modulation and dual-task inference- Adaptation, modulation and dual-task inference

ParametricParametric - Linear and nonlinear interactions- Linear and nonlinear interactions

- Psychophysiological Interactions- Psychophysiological Interactions

A categorical analysisA categorical analysisA categorical analysisA categorical analysis

Experimental designExperimental design

Word generationWord generation GGWord repetitionWord repetition RR

R G R G R G R G R G R GR G R G R G R G R G R G

G - R = Intrinsic word generationG - R = Intrinsic word generation

Differential event-related fMRIDifferential event-related fMRI

Parahippocampal responses to words

BOLD EPI fMRI at 2T, TR BOLD EPI fMRI at 2T, TR 3.2sec. Words presented every 3.2sec. Words presented every

16 secs; (i) studied words or (ii) 16 secs; (i) studied words or (ii) new wordsnew words

BOLD EPI fMRI at 2T, TR BOLD EPI fMRI at 2T, TR 3.2sec. Words presented every 3.2sec. Words presented every

16 secs; (i) studied words or (ii) 16 secs; (i) studied words or (ii) new wordsnew words

Peri-stimulus time {secs}Peri-stimulus time {secs}

SPM{F} SPM{F} testing for testing for

differencesdifferences

studied wordsstudied words

new wordsnew words

SPM{F} testing SPM{F} testing for evoked for evoked responsesresponses

Cognitive ConjunctionsCognitive ConjunctionsCognitive ConjunctionsCognitive Conjunctions

ComponentsComponents

Object Recognition Object Recognition RRPhonological RetrievalPhonological Retrieval PPVisual ProcessingVisual Processing VV

TasksTasks

Object namingObject naming R,P,V,R,P,V,RxPRxPColour namingColour naming P,VP,V

Object viewingObject viewing R,VR,VColour viewingColour viewing VV

The ConjunctionThe Conjunction

[ R,V - V ] & [ R,V,P, [ R,V - V ] & [ R,V,P, RxP RxP - V,P ]- V,P ]R, R, RxPRxP & R = R & R = R

Object recognition responses (R)Object recognition responses (R)

viewing namingviewing naming

A parametric analysisA parametric analysisA parametric analysisA parametric analysis

The [nonlinear] effectThe [nonlinear] effectof time assessed with the SPM{T}of time assessed with the SPM{T}

Nonlinear parametric responses:Nonlinear parametric responses:Nonlinear parametric responses:Nonlinear parametric responses:

Inverted ‘U’ response toInverted ‘U’ response toincreasing word presentationincreasing word presentation

rate in the DLPFCrate in the DLPFCSPM{F}SPM{F}

Regression andRegression and design matrixdesign matrix

42 wpm42 wpm

SPM{F}

Neurometric functions:Neurometric functions:Extrastriate responses to stimuli of increasing duration:Extrastriate responses to stimuli of increasing duration:

Stimulus-specific or contextual effects?Stimulus-specific or contextual effects?

0 exposure duration {ms} 8000 exposure duration {ms} 800

Adaptation of Adaptation of neuronal responsesneuronal responses

AttentionalAttentionalmodulationmodulation

time{ms}time{ms}

SPM{F}SPM{F}

Peri-stimulus timePeri-stimulus time

Hemodynamic responses to words in the left peri-auditory regionHemodynamic responses to words in the left peri-auditory region

60 wpm60 wpm

30 wpm30 wpm

32 secs32 secs

Event-relatedEvent-relatedState-related responsesState-related responses

• BOLD EPI T2* at 2 Tesla TR = 1.7sBOLD EPI T2* at 2 Tesla TR = 1.7s

• 34s epochs of aurally presented words at 0, 10, 15, 30, 60 and 90 words per minute34s epochs of aurally presented words at 0, 10, 15, 30, 60 and 90 words per minute

• 1200 volume time-series1200 volume time-series

Context-sensitive responsesContext-sensitive responsesContext-sensitive responsesContext-sensitive responses

timetimestimulus nstimulus nstimulus n-1stimulus n-1 stimulus n+1stimulus n+1

response nresponse n

interaction between stimuliinteraction between stimuli

Volterra series - a general nonlinear input-output modelVolterra series - a general nonlinear input-output model

response response yy((tt))input input uu((tt))

kernel kernel estimatesestimates

Simulated input

nonlinear saturation

)()(

)(),(

)()(),()}({)(

11

11

0

11 0

i

i

ii

ii

t

iii

t

uu

ty

dduututy

)}({ tu

Nonlinear hemodynamic responsesNonlinear hemodynamic responsesNonlinear hemodynamic responsesNonlinear hemodynamic responses

SPM{F} testing HSPM{F} testing H00: kernel coefficients = h = 0: kernel coefficients = h = 0

kernel coefficients - hkernel coefficients - h

SPM{F}SPM{F}p < 0.001p < 0.001

Nonlinear hemodynamic responses - implicationsNonlinear hemodynamic responses - implicationsNonlinear hemodynamic responses - implicationsNonlinear hemodynamic responses - implications

Hemodynamic response interferenceHemodynamic response interferencein terms of the effect of a prior stimulusin terms of the effect of a prior stimulus

nonlinear saturation

600ms600ms

1400ms1400ms

1400ms1400ms

700ms700ms

42 wpm42 wpm

84 wpm84 wpm

Rate {wpm}Rate {wpm}

Integrated responseIntegrated response

??

42 wpm42 wpm

Rate-dependent responses:Rate-dependent responses:Processing one stimulus in the context of othersProcessing one stimulus in the context of others

ERPs - single wordsERPs - single words

nonlinear interactions

Peri-auditory responses in PET and fMRIPeri-auditory responses in PET and fMRIPeri-auditory responses in PET and fMRIPeri-auditory responses in PET and fMRI

rightrightB

OL

DB

OL

D

Word presentation rateWord presentation rateWord presentation rateWord presentation rate

rCB

FrC

BF

leftleft rightright

Linear rCBFLinear rCBFresponsesresponses

NonlinearNonlinear BOLDBOLD

responsesresponses

A factorial analysisA factorial analysisA factorial analysisA factorial analysis

Time x condition interactions (Time x condition interactions (i.e. adaptationi.e. adaptation))assessed with the SPM{T}assessed with the SPM{T}

Interactions and context-sensitive effectsInteractions and context-sensitive effectsInteractions and context-sensitive effectsInteractions and context-sensitive effects

Context 1Context 1(no naming)(no naming)

Context 2Context 2(naming)(naming)

without A & with Awithout A & with A(e.g.. recognition)(e.g.. recognition)

11 22

4433

A 2 x 2 layoutA 2 x 2 layout

task 1 2 3 4task 1 2 3 4

interaction effectinteraction effect (A x Context)(A x Context)

AA

AA

Context 1Context 1 Context 2Context 2

Object-specific activationsObject-specific activations

Interaction effects in the Interaction effects in the left inferotemporal regionleft inferotemporal region

Context: Context: no naming namingno naming namingad

just

ed r

CB

Fad

just

ed r

CB

F

ComponentsComponentsVisual processingVisual processing VVObject recognition Object recognition RRPhonological retrievalPhonological retrieval PPInteractionInteraction RxPRxP

ConjunctionConjunction(name object - shape) & (view object - shape)(name object - shape) & (view object - shape)= (R += (R + RxP RxP) & R = R) & R = R

InteractionInteraction(name object - shape) - (view object - shape)(name object - shape) - (view object - shape)= (R + = (R + RxPRxP) - R = ) - R = RxPRxP

A PET study of object namingA PET study of object naming

Psychopharmacological studiesPsychopharmacological studies• PET, 6 subjects, 6 conditionsPET, 6 subjects, 6 conditions

• 3 x 2 factorial design, 3 x 2 factorial design, Buspirone x MemoryBuspirone x Memory

sub- supra-sub- supra-

pre-pre-

acute-acute-

post-post-

left parahippocampal left parahippocampal responsesresponses

pre acute post

SCC

timetime

resp

onse

resp

onse

resp

onse

resp

onse

timetime

A direct effect of context = CA direct effect of context = C Context-sensitive effect = S x NContext-sensitive effect = S x N

frequencyfrequency

resp

onse

resp

onse

resp

onse

resp

onse

frequencyfrequency

Dissociating the direct and modulatory effects of contextDissociating the direct and modulatory effects of context

Responses in the right posterior superiorResponses in the right posterior superiortemporal regiontemporal region

to increasing rates (15 - 90 wpm) of word productionto increasing rates (15 - 90 wpm) of word production

whilst repeating words and producing new ones whilst repeating words and producing new ones

7777

8484

rCB

F {

ml/

dl/m

in}

rCB

F {

ml/

dl/m

in}

Interactions between set and event-related responses:Attentional modulation of V5 responses

attention to motion

attention to colour

Non-linear parametric interactionsNon-linear parametric interactionsNon-linear parametric interactionsNon-linear parametric interactions

SPM{F}

Increasing word presentationIncreasing word presentationrate in a subject and patientrate in a subject and patient

with a CVAwith a CVA

Differential responses in theDifferential responses in theleft hippocampusleft hippocampus

Psychophysiological interactionsPsychophysiological interactions

stimulistimuli SetSet

ContextContext

sourcesourcetargettarget

XX

Modulation of Modulation of stimulus-specific stimulus-specific

responsesresponses

Context-sensitiveContext-sensitiveconnectivityconnectivity

sourcesource sourcesource

targettarget targettarget

Psychophysiological interactionsPsychophysiological interactions in the right inferotemporal region:in the right inferotemporal region:

Modulation of face-selectiveModulation of face-selective responses by PPCresponses by PPC

adju

sted

rC

BF

adju

sted

rC

BF

medial parietal activitymedial parietal activity

FacesFaces

ObjectsObjects

Face stimuliFace stimuli

PPCPPC

ITIT

SPM{Z}SPM{Z}

PsychophysiologicalPsychophysiological interactions:interactions:

Attentional modulation ofAttentional modulation ofV2 - V5 contributionV2 - V5 contribution

AttentionAttention

V2V2

V5V5

attention

no attention

V2 activityV2 activity

V5

acti

vity

SPM{T}SPM{T}

timetime

V5

acti

vity