The role of resting state networks in focal neocortical seizures.

S Kathleen Bandt,Kareem W Ayoub,Ammar H Hawasli,Mrinal Pahwa,Eric C Leuthardt,Carl D Hacker,David T Bundy,Mohit Sharma

doi:10.1371/journal.pone.0107401

Abstract

ObjectiveThe role of resting state functional networks in epilepsy is incompletely understood. While some pathologic diagnoses have been shown to have maintained but altered resting state connectivity, others have implicated resting state connectivity in disease progression. However little is known about how these resting state networks influence the behavior of a focal neocortical seizure.MethodsUsing data taken from invasively monitored patients with intractable focal neocortical epilepsy, we evaluated network connectivity (as determined by oscillatory covariance of the slow cortical potential (<0.5 Hz)) as it relates to neocortical seizure foci both in the interictal and ictal states.ResultsSimilar to what has been shown in the past for sleep and anesthesia, electophysiologic resting state networks that are defined by this slow cortical potential covariance maintain their topographic correlation structure throughout an ictal event. Moreover, in the context of focal epilepsy in which the seizure has a specific site of onset, seizure propagation is not chaotic or random. Rather, the seizure (reflected by an elevation of high frequency power) preferentially propagates along the network that contains the seizure onset zone.SignificanceTaken together, these findings further undergird the fundamental role of resting state networks, provide novel insights into the network-influenced behavior of seizures, and potentially identify additional targets for surgical disconnection including informing the location for the completion of multiple subpial transections (MSPTs).

Highlights

The brain is becoming increasingly understood as a dynamically interconnected compilation of functional networks
Given that the deposition of Ab has been implicated in the disease progression of Alzheimer’s Disease (AD) [17], this provides a provocative link between the structural disease process of AD and the underlying functional connectivity related to its manifestation
Resting State Network Connectivity Related to a Neocortical Seizure Focus

Summary

Introduction

The brain is becoming increasingly understood as a dynamically interconnected compilation of functional networks These networks possess both resting state and active state profiles which can be recognized by a number of signal detection modalities including electrocorticography (ECoG) and functional magnetic resonance imaging (fMRI) [1,2,3,4,5,6,7,8]. These networks remain intact and identifiable through both sleep and general anesthesia [7,9]. While these findings support the notion that the DMN in some way chronically guides the pathologic process over years, little is currently known about how a resting state network impacts a transient electrophysiologic perturbation such as a focal seizure

Methods

Results

Conclusion