EEG connectivity pattern: A window into the schizophrenia mind?

Abstract

Schizophrenia (SZ) is a chronic and severe mental disorder, characterized by a set of positive, negative, and cognitive symptoms. It has been linked to abnormal activation, connectivity, and integration within distributed brain areas. EEG-a non-invasive electrophysiological monitoring method-enables direct measurement of whole-brain electrical activity, known as oscillations. Such coordinated brain oscillations are considered to play key roles in neural communication, integration, and computation, and therefore offer an exceptional window into the dynamics of healthy and disturbed brain function. In recent years, a multitude of methods have been incorporated to estimate functional and effective connectivity between local and large-scale neural populations. The purpose of this chapter is to introduce the reader to the state-of-the-art EEG tools that have been repeatedly used to investigate pathophysiological circuits underlying the heterogeneous symptoms of SZ. Analytical approaches, such as microstate analysis, coherence, phase locking value, phase lag index, phase-amplitude coupling, lagged phase synchronization, as well as Granger causality, and dynamic causal modelling will be presented. Although until today, no gold standard of EEG connectivity approaches has yet emerged, each of these metrics have led to tremendous progress in understanding discrete pathophysiological circuits that may hold promise for new diagnostic and disease treatment strategies.