Magnetoencephalography

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

IFCN-endorsed practical guidelines for clinical magnetoencephalography (MEG)

Magnetoencephalography (MEG) records weak magnetic fields outside the human head and thereby provides millisecond-accurate information about neuronal currents supporting human brain function. MEG and electroencephalography (EEG) are closely related complementary methods and should be interpreted together whenever possible. This manuscript covers the basic physical and physiological principles of MEG and discusses the main aspects of state-of-the-art MEG data analysis. We provide guidelines for best practices of patient preparation, stimulus presentation, MEG data collection and analysis, as well as for MEG interpretation in routine clinical examinations. In 2017, about 200 whole-scalp MEG devices were in operation worldwide, many of them located in clinical environments. Yet, the established clinical indications for MEG examinations remain few, mainly restricted to the diagnostics of epilepsy and to preoperative functional evaluation of neurosurgical patients. We are confident that the extensive ongoing basic MEG research indicates potential for the evaluation of neurological and psychiatric syndromes, developmental disorders, and the integrity of cortical brain networks after stroke. Basic and clinical research is, thus, paving way for new clinical applications to be identified by an increasing number of practitioners of MEG. (C) 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V.Peer reviewe

Clinical Management and Evolving Novel Therapeutic Strategies for Patients with Brain Tumors

A dramatic increase in knowledge regarding the molecular biology of brain tumors has been established over the past few years, and this has lead to the development of novel therapeutic strategies for these patients. In this book a review of the options available for the clinical management of patients with these tumors are outlined. In addition advances in radiology both for pre-operative diagnostic purposes along with surgical planning are described. Furthermore a review of newer developments in chemotherapy along with the evolving field of photodynamic therapy both for intra-operative management and subsequent therapy is provided. A discussion of certain surgical management issues along with tumor induced epilepsy is included. Finally a discussion of the management of certain unique problems including brain metastases, brainstem glioma, central nervous system lymphoma along with issues involving patients with a brain tumor and pregnancy is provided

Exploring Gustatory Neural Coding and the Influence of Appetite and Expectancy

The purpose of this thesis was to explore human gustatory processing and how it is influenced by appetite and expectancy. The initial two years of the doctorate were dedicated to developing a gustometer mechanism and taste stimulus set to employ in the experimental investigations. Event-related potentials (ERPs), source-localised ERPs and event-related de-synchronisations and synchronisations (ERD/S) were then evaluated in response to taste characteristics under a variety of conditions. The first experiment assessed the ERP, source-localisation and ERD/S components associated with the processing of taste quality (sweet, salt, bitter, water), intensity (neutral, weak, medium, strong) and hedonicity (pleasant, unpleasant, neutral). Gustatory stimulation evoked activations within the primary gustatory cortex (PGC) and intensity was represented in early ERP epochs and by alpha- and beta-band ERD. Hedonicity was coded in late ERP epochs and by alpha-band ERD. Taste quality coding was difficult to determine from the EEG data. The second experiment compared the processing of pleasant sweet and unpleasant bitter tastes during states of hunger following overnight fasting and satiety induced by a standardised liquid meal. Hunger and satiety evoked maximal responses to tastes from limbic regions. Hunger greatly enhanced ERP and beta-band ERS responses to tastes in general. However, responses to sweet tastes were dependent on hunger state; with enhanced neural signals in response to sweet taste after satiating on a sweet meal - suggesting differential attentional and evaluative mechanisms employed under fasted and fed conditions. A final experiment examined the influence of cue-elicited expectancy on the processing of sweet tastes. Participants were validly or invalidly cued to expect a low- or high-concentration of sweet taste; both behavioural and neural responses to invalidly cued tastes assimilated to those that were produced by the taste the participants were cued to receive. These effects began ~100 ms after the onset of the tastes, suggesting that expectancy influences the early perceptual processing of taste. The overall findings of this thesis provide some of the first accounts of the temporal, source-localised and oscillatory dynamics of gustatory coding. The results also provide important implications for understanding how people’s experience of taste and food can be modified by appetite and expectancy