Magnetoencephalography

Magnetoencephalography (MEG) is an invaluable functional brain imaging technique that provides direct, real-time monitoring of neuronal activity necessary for gaining insight into dynamic cortical networks. Our intentions with this book are to cover the richness and transdisciplinary nature of the MEG field, make it more accessible to newcomers and experienced researchers and to stimulate growth in the MEG area. The book presents a comprehensive overview of MEG basics and the latest developments in methodological, empirical and clinical research, directed toward master and doctoral students, as well as researchers. There are three levels of contributions: 1) tutorials on instrumentation, measurements, modeling, and experimental design; 2) topical reviews providing extensive coverage of relevant research topics; and 3) short contributions on open, challenging issues, future developments and novel applications. The topics range from neuromagnetic measurements, signal processing and source localization techniques to dynamic functional networks underlying perception and cognition in both health and disease. Topical reviews cover, among others: development on SQUID-based and novel sensors, multi-modal integration (low field MRI and MEG; EEG and fMRI), Bayesian approaches to multi-modal integration, direct neuronal imaging, novel noise reduction methods, source-space functional analysis, decoding of brain states, dynamic brain connectivity, sensory-motor integration, MEG studies on perception and cognition, thalamocortical oscillations, fetal and neonatal MEG, pediatric MEG studies, cognitive development, clinical applications of MEG in epilepsy, pre-surgical mapping, stroke, schizophrenia, stuttering, traumatic brain injury, post-traumatic stress disorder, depression, autism, aging and neurodegeneration, MEG applications in cognitive neuropharmacology and an overview of the major open-source analysis tools.

This is a practical book on MEG that covers a wide range of topics. The book begins with a series of reviews on the use of MEG for clinical applications, the study of cognitive functions in various diseases, and one chapter focusing specifically on studies of memory with MEG. There are sections with chapters that describe source localization issues, the use of beamformers and dipole source methods, as well as phase-based analyses, and a step-by-step guide to using dipoles for epilepsy spike analyses. The book ends with a section describing new innovations in MEG systems, namely an on-line real-time MEG data acquisition system, novel applications for MEG research, and a proposal for a helium re-circulation system. With such breadth of topics, there will be a chapter that is of interest to every MEG researcher or clinician.

This book presents an overview of the recent advances in clinical applications of magnetoencephalography (MEG). With the expansion of MEG to neuroscience, its clinical applications have also been actively pursued. Featuring contributions from prominent experts in the fields, the book focuses on the current status of the application of MEG, not only to each nervous system but also to various diseases such as epilepsy, neurological disorders, and psychiatric disorders, while also examining the feasibility of using MEG for these diseases. Clinical Applications of Magnetoencephalography offers an indispensable resource for neurologists, neurosurgeons, pediatricians, and psychiatrists, as well as researchers in the field of neuroscience.

Fifty Years of Magnetoencephalography celebrates the first half century of research in and clinical applications of magnetoencephalography (MEG). It catalogs and documents its evolution as a means of imaging the ongoing activity of the brain and the activation of particular neuronal networks within it that mediate sensory motor and higher functions like language. The volume's first section looks at the discovery of MEG and its first tentative applications by three of its founders. The following sections detail the rapid progress in the development of the instrumentation necessary for recording noninvasively the magnetic signals on the head that are associated with the brain activity; improvements in the techniques for analyzing the magnetic signals and reconstructing, on their basis, the functional images of brain activity; and improvements in our understanding of the nature and significance of those signals. Subsequent sections of the book detail the main clinical applications of MEG in localizing brain areas that contain sources of epileptiform activity and areas encompassing parts of functional networks essential for motor and sensory function as well as for language that have become an essential part of planning for brain surgery in many epilepsy and tumor surgery centers around the world. In addition, several chapters describe the most current efforts aiming at expanding the utility of MEG in clinical diagnosis and theoretical research.

This issue of Neuroimaging Clinics of North America focuses on Magnetoencephalography (MEG), and is edited by Drs. Roland Lee and Mingxiong Huang. Articles will include: MEG signal processing, forward modeling, MEG inverse source imaging, and Coherence analysis; Magnetoencephalography for pre-surgical functional mapping; Magnetoencephalography for mild TBI and PTSD; Magnetoencephalography for autism; Magnetoencephalography for schizophrenia; Magnetoencephalography for Alzheimer's disease; Pediatric Magnetoencephalography; The MEG Measurement Techniques; MEG and Language/Linguistics; MEG for Epilepsy; Integration of MEG results into the patient workup – Merging multiple modalities; and more!

Research on the human brain development has seen an upturn in the past years mostly due to novel neuroimaging tools that became available to study the anatomy and function of the developing brain. Magnetic Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI) are beginning to be used more frequently in children to determine the gross anatomy and structural connectivity of their brain. Functional MRI and Near-Infrared Spectroscopy (NIRS) determine the hemodynamics and electroencephalography (EEG) the electrophysiological functions of the developing human brain. Magnetoencephalography (MEG) complements EEG as the only other technique capable of directly measuring the developing brain electrophysiology. Although MEG is still being used relatively rarely in pediatric studies, the recent development in this technology is beginning to demonstrate its utility in both basic and clinical neurosciences. MEG seems to be quite attractive for pediatric use, since it measures the human brain activity in an entirely passive manner without possessing any conceivable risk to the developing tissue. MEG sessions generally require minimal patient preparation, and the recordings are extremely well tolerated from children. Biomagnetic techniques also offer an indirect way to assess the functional brain and heart activity of fetuses in humans in utero by measuring the magnetic field outside the maternal abdomen. Magnetic field produced by the electrical activity in the heart and brain of the fetus is not attenuated by the vernix, a waxy film covering its entire skin. A biomagnetic instrument specifically designed for fetal studies has been developed for this purpose. Fetal MEG studies using such a system have shown that both spontaneous brain activity and evoked cortical activity can be measured from outside the abdomen of pregnant mothers. Fetal MEG may become clinically very useful for implementation and evaluation of intervention programs in at-risk populations. Biomagnetic instruments have also been developed for specifically measuring the brain activity in newborns, infants and older children. MEG studies have shown the usefulness of MEG for localizing active regions in the brain and also for tracking the longitudinal maturation of various sensory systems. Studies of pediatric patients are beginning to show interesting functional pathology in autism spectrum disorder, cerebral palsy, epilepsy and other types of neurological and psychiatric disorders (Down syndrome, traumatic brain injury, Tourette syndrome, hearing deficits, childhood migraine). In this eBook, we compile the state of the art MEG and other neuroimaging studies focused on pediatric population in both health and disease. We believe a review of the recent studies of human brain development using MEG is quite timely, since we are witnessing advances not only in the instrumentation optimized for the pediatric population, but also in the research based on various types of MEG systems designed for both human fetuses in utero and neonates and older children.

An evaluation of the diagnostic utility of MEG and its clinical role in relation to EEG. Sato (Chief of EEG Laboratory and Neurophysiology Unit, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland) and other investigators who are at the forefront of MEG research report their own firsthand experiences with this new technology and explore its possible future applications. Annotation copyrighted by Book News, Inc., Portland, OR