Multimodal Integration: fMRI, MRI, EEG, and MEG - Advance Image Processing in Magnetic Resonance Imaging - page 215

8

Multimodal Integration:
fMRI, MRI, EEG,
and MEG

Yaroslav O. Halchenko, Stephen José Hanson,
and Barakk A. Pearlmutter

CONTENTS

Overview ...........................................................................................................224
8.1 Introduction..............................................................................................224

8.2 Source Localization in EEG and MEG ..................................................225

8.2.1 Assumptions Underlying Integration of EEG

and MEG .....................................................................................226

8.2.2 Forward Modeling .......................................................................228

8.2.3 The Inverse Problem ...................................................................229

8.2.3.1 Equivalent Current Dipole Models ..............................229

8.2.3.2 Linear Inverse Methods: Distributed ECD ..................230

8.2.3.3 Beamforming................................................................233

8.3 Multimodal Experiments .........................................................................235

8.3.1 Measuring EEG during MRI: Challenges

and Approaches ...........................................................................235

8.3.2 Experimental Design Limitations ...............................................237

8.4 Multimodal Analysis ...............................................................................238

8.4.1 Using Anatomical MRI ...............................................................238

8.4.1.1 Registration of EEG and MEG to MRI.......................239

8.4.1.2 Segmentation and Tessellation.....................................240

8.4.1.3 Forward Modeling of EEG and MEG .........................241

8.4.2 Forward Modeling of BOLD Signal ...........................................241

8.4.2.1 Convolutional Model of BOLD Signal .......................243

8.4.2.2 Neurophysiologic Constraints......................................244

8.4.3 Analysis Methods ........................................................................246

8.4.3.1 Correlative Analysis of EEG and MEG

with fMRI ....................................................................246

8.4.3.2 Decomposition Techniques ..........................................247

8.4.3.3 Equivalent Current Dipole Models ..............................248

223