Event-Related Brain Potentials in Depression: Clinical, Cognitive, and Neurophysiological Implications

Abstract

Individuals who have a depressive disorder commonly experience difficulties with concentration, attention, and other cognitive functions, such as memory and executive control. The recording of event-related brain potentials (ERPs) provides a noninvasive means for studying cognitive deficits in depressive disorders and their underlying neurophysiological mechanisms. This chapter reviews the findings of studies measuring ERPs in depressed patients during a variety of sensory, cognitive, and emotional tasks in order to contribute to a better understanding of the specific processes and neurophysiological mechanisms that are dysfunctional in depressive disorders. It highlights the clinical relevance of ERP findings in depressed patients by describing the relation of patients’ ERPs to their clinical features, most notably severity of depressive symptoms, diagnostic subtype, and therapeutic response to treatments. From a methodological perspective, it presents new findings illustrating the power of combining current source density (CSD) and principal components analysis (PCA) techniques, which take better advantage of both the temporal resolution of ERPs and the spatial resolution of dense electrode arrays than traditional analysis methods of reference-dependent surface potentials.