A Unifying Explanation of Primary Generalized Seizures Through Nonlinear Brain Modeling and Bifurcation Analysis

TLDR

The model represents cortical activity as wave propagation with delays, membrane dynamics, and corticothalamic feedback, and prior work has validated it in healthy states and predicted seizure phenomena. The study aims to explain key features of primary generalized epilepsies by analyzing the bifurcations of a nonlinear brain mean‑field model, presenting the first unifying explanation of these seizures. The authors use bifurcation analysis of a nonlinear brain mean‑field model to provide a unifying explanation of generalized seizures. Mapping the bifurcation set predicts periodic, chaotic, and multistable dynamics, and electrophysiological data confirm that the model’s global bifurcation diagram explains the core differences between tonic–clonic and absence seizures.

Abstract

The aim of this paper is to explain critical features of the human primary generalized epilepsies by investigating the dynamical bifurcations of a nonlinear model of the brain's mean field dynamics. The model treats the cortex as a medium for the propagation of waves of electrical activity, incorporating key physiological processes such as propagation delays, membrane physiology, and corticothalamic feedback. Previous analyses have demonstrated its descriptive validity in a wide range of healthy states and yielded specific predictions with regards to seizure phenomena. We show that mapping the structure of the nonlinear bifurcation set predicts a number of crucial dynamic processes, including the onset of periodic and chaotic dynamics as well as multistability. Quantitative study of electrophysiological data supports the validity of these predictions. Hence, we argue that the core electrophysiological and cognitive differences between tonic–clonic and absence seizures are predicted and interrelated by the global bifurcation diagram of the model's dynamics. The present study is the first to present a unifying explanation of these generalized seizures using the bifurcation analysis of a dynamical model of the brain.