Failure of adaptive self-organized criticality during epileptic seizure attacks

TL;DR

This study shows that during epileptic seizures, brain activity deviates from critical dynamics, indicating a failure of adaptive self-organized criticality, which may have implications for understanding seizure mechanisms.

Contribution

It provides empirical evidence that epileptic seizures involve a breakdown of critical brain dynamics and compares this with a computational SOC model to understand underlying mechanisms.

Findings

Neuronal activity deviates from power-law distribution during seizures

Brain dynamics fail to exhibit criticality during epileptic attacks

Adaptive SOC models help explain seizure-related deviations

Abstract

Critical dynamics are assumed to be an attractive mode for normal brain functioning as information processing and computational capabilities are found to be optimized there. Recent experimental observations of neuronal activity patterns following power-law distributions, a hallmark of systems at a critical state, have led to the hypothesis that human brain dynamics could be poised at a phase transition between ordered and disordered activity. A so far unresolved question concerns the medical significance of critical brain activity and how it relates to pathological conditions. Using data from invasive electroencephalogram recordings from humans we show that during epileptic seizure attacks neuronal activity patterns deviate from the normally observed power-law distribution characterizing critical dynamics. The comparison of these observations to results from a computational model exhibiting self-organized criticality (SOC) based on adaptive networks allows further insights into the underlying dynamics. Together these results suggest that brain dynamics deviates from criticality during seizures caused by the failure of adaptive SOC.