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SPM 2002 Experimental Design Daniel Glaser Institute of Cognitive Neuroscience, UCL Slides from: Rik Henson, Christian Buchel, Karl Friston, Chris Frith, Cathy Price,Ray Dolan The Wellcome Department of Cognitive Neurology, UCL London UK http//:www.fil.ion.ucl.ac.uk/spm

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Data transformations RealignmentSmoothing Normalisation General linear model Statistical parametric map (SPM) Image time-series Parameter estimates Design matrix Template Kernel Gaussian field theory p <0.05 Statisticalinference

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SPM{T} speed isoluminant stimuli (even) isochromatic stimuli (odd) V5 + + Stimuli

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A taxonomy of design Categorical designs Categorical designs Subtraction - Pure insertion and cognitive subtraction - Differential event-related fMRI Conjunction - Testing multiple hypotheses Parametric designs Parametric designs Linear - Cognitive components and dimensions Nonlinear- Polynomial expansions and neurometric functions - Nonlinear event-related fMRI Factorial designs Factorial designs Categorical- Additive factors and pure insertion - Psychopharmacological designs - Adaptation, modulation and dual-task inference Parametric- Linear and nonlinear interactions - Psychophysiological Interactions

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A categorical analysis Experimental design Word generationG Word repetitionR R G R G R G R G R G R G G - R = Intrinsic word generation

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Differential event-related fMRI Parahippocampal responses to words BOLD EPI fMRI at 2T, TR 3.2sec. Words presented every 16 secs; (i) studied words or (ii) new words Peri-stimulus time {secs} SPM{F} testing for differences studied words new words SPM{F} testing for evoked responses

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Cognitive Conjunctions Components Object Recognition R Phonological RetrievalP Visual ProcessingV Tasks Object namingR,P,V,RxP Colour namingP,V Object viewingR,V Colour viewingV The Conjunction [ R,V - V ] & [ R,V,P, RxP - V,P ] R, RxP & R = R Object recognition responses (R) viewing naming

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A parametric analysis The [nonlinear] effect of time assessed with the SPM{T}

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Nonlinear parametric responses: Inverted ‘U’ response to increasing word presentation rate in the DLPFC SPM{F} Regression and design matrix design matrix 42 wpm

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SPM{F} Neurometric functions: Extrastriate responses to stimuli of increasing duration: Stimulus-specific or contextual effects? 0 exposure duration {ms} 800 Adaptation of neuronal responses Attentionalmodulation time{ms}

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SPM{F} Peri-stimulus time Hemodynamic responses to words in the left peri-auditory region 60 wpm 30 wpm 32 secs Event-related State-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 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

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Context-sensitive responses time stimulus n stimulus n-1 stimulus n+1 response n interaction between stimuli

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Volterra series - a general nonlinear input-output model response y(t) input u(t) kernel estimates Simulated input nonlinear saturation

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Nonlinear hemodynamic responses SPM{F} testing H 0 : kernel coefficients = h = 0 kernel coefficients - h SPM{F} p < 0.001

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Nonlinear hemodynamic responses - implications Hemodynamic response interference in terms of the effect of a prior stimulus nonlinear saturation

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600ms 1400ms 1400ms 700ms 42 wpm 84 wpm Rate {wpm} Integrated response ? 42 wpm Rate-dependent responses: Processing one stimulus in the context of others ERPs - single words nonlinear interactions

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Peri-auditory responses in PET and fMRI right BOLD Word presentation rate rCBF leftright Linear rCBF responses Nonlinear BOLD BOLDresponses

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

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Interactions and context-sensitive effects Context 1 (no naming) Context 2 (naming) without A & with A (e.g.. recognition) A 2 x 2 layout task task interaction effect (A x Context) (A x Context) A A Context 1 Context 2

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Object-specific activations Interaction effects in the left inferotemporal region Context: no naming naming adjusted rCBF Components Visual processingV Object recognition R Phonological retrievalP InteractionRxP Conjunction (name object - shape) & (view object - shape) = (R + RxP) & R = R Interaction (name object - shape) - (view object - shape) = (R + RxP) - R = RxP A PET study of object naming

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Psychopharmacological studies PET, 6 subjects, 6 conditionsPET, 6 subjects, 6 conditions 3 x 2 factorial design, Buspirone x Memory3 x 2 factorial design, Buspirone x Memory PET, 6 subjects, 6 conditionsPET, 6 subjects, 6 conditions 3 x 2 factorial design, Buspirone x Memory3 x 2 factorial design, Buspirone x Memory sub- supra- pre- acute- post- left parahippocampal responses pre acute post

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SC time response response time A direct effect of context = C Context-sensitive effect = S x N frequency responseresponse frequency Dissociating the direct and modulatory effects of context

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Responses in the right posterior superior temporal region to increasing rates ( wpm) of word production whilst repeating words and producing new ones rCBF {ml/dl/min}

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Interactions between set and event-related responses: Attentional modulation of V5 responses attention to motion attention to colour

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Non-linear parametric interactions SPM{F} Increasing word presentation rate in a subject and patient with a CVA Differential responses in the left hippocampus

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Psychophysiological interactions stimuli Set Context source target X Modulation of stimulus-specific responses Context-sensitiveconnectivity source source target target

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Psychophysiological interactions in the right inferotemporal region: in the right inferotemporal region: Modulation of face-selective responses by PPC responses by PPC adjusted rCBF medial parietal activity Faces Objects Face stimuli PPC IT SPM{Z}

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Psychophysiological interactions: interactions: Attentional modulation of V2 - V5 contribution Attention V2 V5 attention no attention V2 activity V5 activity SPM{T} time

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