Seizures at the scale of individual neurons

Abstract

This scientific commentary refers to ‘Single unit action potentials in humans and the effect of seizure activity’ by Merricks et al. (doi:10.1093/brain/awv208). Seizures are commonly accepted to be events characterized by brief periods of abnormal neuronal firing. However, the basic physiology of what occurs during a seizure remains poorly understood. This significant shortfall prevents us from developing new treatments for the one-third of patients with epilepsy who do not obtain substantial control of their seizures with maximal medical therapy. Beginning in the 1950s, researchers began to address the physiology gap with recordings in models of seizures, including recordings of neural activity in small numbers of individual neurons. First in animal models and now more recently in human patients, studies of individual neurons have described how neural activity changes as seizures start, spread and terminate. These studies, however, have also fuelled additional questions about how seizures can be defined, characterized and ultimately brought under control. The canonical view of a typical seizure is that it represents excessive or ‘hypersynchronous’ activity in a large group of neurons. This textbook model is a satisfactory shorthand for the overall process of a seizure, but neglects noteworthy heterogeneity and important unknowns. In the last decade or so, work from many groups using a …