EEG-fMRI: Physiological Basis, Technique, and Applications

EEG-fMRI: Physiological Basis, Technique, and Applications. Christoph Mulert and Louise Lemieux (Editors). Springer 2010, 529 pages, 142 illustrations, $179.00.

This textbook covers advancing field of multimodal data acquisition strategies, giving detailed technical challenges that need to be overcome in order to study brain function.  EEG-fMRI: Physiological Basis, Technique, and Applications is a well written and comprehensive book on the state of the art technology that combines EEG and fMRI as an invaluable tool to study brain function.  The book is primarily based on combining EEG data which provides very high temporal information but it lacks spatial information which can be provided by fMRI.  The book is organized into three parts with chapters of each part being authored by various authorities in the field.  Part I “Background” reviews the basic physics and physiological process that leads to signal changes in fMRI.  It also provides the signal origins and measurements of electrophysiological signals with EEG.  Part II “Technical and Methodological Aspect of Combined EEG-fMRI Experiments” reviews challenges faced on EEG instrumentation, as it pertains to patient safety, origins and reduction of EEG artefacts, and minimizing MR image artefacts.  Part III “Applications of EEG-fMRI” reviews several applications where multimodal EEG and fMRI can be used to study brain function.

The book begins with a comprehensive review of multimodal modal functional imaging and data integration that can be used simultaneously as it pertains to EEG and fMRI to study actual brain events that are relevant to epilepsy and other cognitive neuroscience applications.  There are two chapters that review fundamentals of MRI and fMRI techniques.  It introduces the reader to synaptic activity and local field potentials followed by the haemodynamic response of BOLD fMRI.  There are other chapters that introduce the reader to value of combining EEG and fMRI.

Part II focuses on the many different aspects of technical issues one faces when collecting EEG data in the MRI system.  One chapter is dedicated to EEG instrumentation that needs to be modified for patient safety reasons.  The metal electrodes used on EEG cap could induce localized heating when placed in MRI system, the EEG leads have to be modified to minimize induction of electrical currents from RF and imaging gradients.  There two chapter dedicated to EEG artifacts when used in MRI system, detail description of cardiac related artifacts and imaging gradient artifacts on EEG data are presented.  Several methods are proposed to remove these artifacts from EEG data so that one can use it simultaneously with MRI.  Other chapters discuss MR image quality issues such as geometric distortion, ghosting, and bulk head motion.  There is one chapter dedicated to issues specific to high magnetic fields of 3 Tesla or greater.  The final chapter describes different strategies of EEG and fMRI data acquisition; there is detailed discussion on advantages and disadvantages of interleaved methods using triggered or sparse scanning approach and simultaneous approach.

The application oriented section of the book, Part III, describes several applications in which simultaneous use of EEG and fMRI can provide further insight into brain function during resting state and sleep research.  There are two chapters dedicated to epilepsy, which has been the driving force of this simultaneous EEG and fMRI approach.  There is detailed description of using EEG data to identify the rest and event blocks for fMRI data processing; most of the epileptic events occur in random fashion, hence it is crucial to identify the ictal and interictal events during fMRI data acquisition.  There are other event related applications that use simultaneous EEG and fMRI in pain research, visual, auditory systems, and cognitive function as it pertains to attention, executive function, and memory.

This book was written primarily for the study of epilepsy and has given a very good insight into advantages of simultaneous data acquisition of EEG and fMRI as well as using both data sets to identify when the neurophysiological events takes place on EEG, which would lead to haemodynamic response that could be characterized in fMRI data.  Fusion of this information would enable one to pin-point the spatial location of the neurophysiological event or events.  There are extensive discussions of the physiological principals, practical aspects of measurement, artifact reduction and analysis of the data.  This book reviews all applications, which reside mainly in the fields of epilepsy, sleep research, cognitive neuroscience, and clinical use in neurology and psychiatry.  The chapters within each section were appropriately selected to facilitate the reader’s comprehension of these complex topics.  As a whole, the text is very accurate, but there were certain sections in some chapters that referenced other sections of the book for details, as well as other references, that made it difficult to comprehend and understand the main point of the section.

This book provides useful resource to neuroscientist, psychiatrists, and engineers who are interested in performing simultaneous EEG-fMRI experiments by presenting detailed description on a large number of applications.  It is particularly useful to the research community who study event related changes that occur at neurophysiological levels with EEG and simultaneously acquired fMRI to spatially locate the region of activation in epilepsy, sleep, and resting state to study default mode network.  For years to come, these event related conditions will be studied under experimental conditions, and this book will be useful resource for the scientists conducting such studies.

EEG-fMRI: Physiological Basis, Technique, and Applications