Incorporating higher dimensions in joint decomposition of EEG- fMRI Wout Swinnen, BIOMED KU Leuven
Introduction: EEG and fMRI EEGfMRI
Introduction: EEG and fMRI
JointICA
(B. Mijovic, 2013) Proved that assumption is correct But one EEG channel only
Incorporate multiple channels in JointICA
Materials Visual detection task (Mijovic, 2013) Down-left visual stimulus Press of button 18 subjects, fMRI and EEG read non-simultaneously Preprocessing: o EEG ERP’s Averaged and interpolated o fMRI PSC maps Using SPM software and contrasting fMRI signal after stimulus vs background
Results: JointICA
Results: sJointICA
First 18 IC’s of 54 for electrode set [PO7,Oz,PO8] Results: ERP parts of the IC’s make up smaller time resolution But ERP phenomenon described is less natural (narrow peak) and more hard to interpret
Results: tJointICA
All 18 IC’s for electrode set [PO7,Oz,PO8] Results: Only strongest ERP characteristics described (such as N1) No good IC’s for weaker ERP characteristics (such as P1,...)
Conclusions JointICA: Meaningful decomposition showing underlying physiological mechanisms, but only 1 channel sJointICA: o Results are more difficult to interpret tJointICA: o IC’s show more pronounced and robust fMRI sources for certain patterns of ERP activity o More information on strong ERP characteristics at expense of weak ERP characteristics
Questions?