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Alois Schlögl University of Technology Graz, Austria . Analyzing EEG Coupling. COST B27 ENOC Joint WGs Meeting Swansea UK, 16-18 September 2006. Offer: Methods for analysing EEG coupling using Multivariate autoregressive modelling - PowerPoint PPT Presentation
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Analyzing EEG Coupling
Alois Schlögl University of Technology Graz, Austria
COST B27 ENOC Joint WGs Meeting Swansea UK, 16-18 September 2006
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• Offer: – Methods for analysing EEG coupling using
Multivariate autoregressive modelling– Coherency, PDC, DTF, phase, etc. – BioSig http://biosig.sf.net
• Asking for:– EEG data on interesting research topics– collaboration
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Multivariate AutoRegressive (MVAR) models
• Multivariate: spatio-temporal correlation
• Estimators:– Levinson-Wiggins-Robinson (LWR):
Multivariate Yule-Walker– Nutall-Strand method (multivariate burg method)– Vieira-Morf (multivariate geometric lattice)
• Software: – TSA-toolbox: MVAR.M– BioSig http://biosig.sf.net
Schlögl (2006), Comparison of MVAR estimators, Signal Processing.
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5Coupling almost all the time in all frequencies !?
Time-Frequency AnalysisPDC (Hypothesis: PDC>0)
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Subject K3Left hand
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Event-related PDC (Hypothesis: PDC != ref)
Increases and decreases of coupling can be observed !
pdc<ref
pdc>ref
Subject K3Left handref=pdc(0-3s)
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MVAR estimators
Comparison of • ARFIT• Multichannel Yule-
Walker• Multichannel Burg
(Nutall-Strand)
Schlögl, A. (2006) Comparison of Multivariate Autoregressive Estimators.Signal processing
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mean square predicition error
rank
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N=50N=60N=70N=100N=400
Nuttall-Strand with unbiased covariance
Nuttall-Strand with biased covariance
ARFIT-0
multichannel Yule-Walker
ARFIT
N=40
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Signal processing (II)
• Spectrum • Coherence (absCOH, imagCOH)• Partial coherence (pCOH)• Partial directed coherence (PDC) • Directed transfer function (DTF)• Full-Frequency DTF (ffDTF)• Directed coupling (DC) • Phase
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Auto/Crossspectra & Coherence
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logS
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Imaginare und partiel Coherence
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Directed transfer function DTF & partial directed coherence (PDC)
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PDC
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Thank You for the Attention
• References: – Schlögl, 2006, Comparison of Multivariate
Autoregressive Estimators.Signal processing
– Schlögl and Supp (in press), Progress In Brain Research
Contact: Alois Schlögl [email protected]://biosig.sf.net
14Coupling almost all the time in all frequencies !?
DTF (Hypothesis: DTF>0)
0
1
Subject K3Left hand
15Increases and decreases of coupling can be observed !
pdc<ref
pdc>ref
Subject K3Right handref=pdc(0-3s)
Event-related PDC (Hypothesis: PDC != ref)