Disrupted cortical brain network in post-traumatic stress disorder patients: a resting-state electroencephalographic study

M Shim,S-H Lee,C-H Im

doi:10.1038/tp.2017.200

M Shim, S-H Lee + Show 1 more

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https://doi.org/10.1038/tp.2017.200

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Abstract

This study aimed to examine the source-level cortical brain networks of post-traumatic stress disorder (PTSD) based on the graph theory using electroencephalography (EEG). Sixty-six cortical source signals were estimated from 78 PTSD and 58 healthy controls (HCs) of resting-state EEG. Four global indices (strength, clustering coefficient (CC), path length (PL) and efficiency) and one nodal index (CC) were evaluated in six frequency bands (delta, theta, alpha, low beta, high beta and gamma). PTSD showed decreased global strength, CC and efficiency, in delta, theta, and low beta band and enhanced PL in theta and low beta band. In low beta band, the strength and CC correlated positively with the anxiety scores, while PL had a negative correlation. In addition, nodal CCs were reduced in PTSD in delta, theta and low beta band. Nodal CCs of theta band correlated negatively with rumination and re-experience symptom scores; while, nodal CCs in low beta band correlated positively with anxiety and pain severity. Inefficiently altered and symptom-dependent changes in cortical networks were seen in PTSD. Our source-level cortical network indices might be promising biomarkers for evaluating PTSD.

Highlights

Post-traumatic stress disorder (PTSD) is a unique mental illness with dysfunctional brain activities, demonstrated by symptoms such as re-experiences, avoidance and hyperarousal, as defined by the Diagnostic and Statistical Manual of Mental disorders (DSM-5).[1]
We have previously investigated complex networks in PTSD, using three network indices based on graph theory, which has recently been introduced as a theory for constructing human brain networks
We found reduced frontal nodal connection strength and communication efficiency in beta and gamma frequency bands in PTSD, as compared to healthy controls (HCs), and found that network values were significantly correlated with PTSD symptom scales

Summary

Introduction

Post-traumatic stress disorder (PTSD) is a unique mental illness with dysfunctional brain activities, demonstrated by symptoms such as re-experiences, avoidance and hyperarousal, as defined by the Diagnostic and Statistical Manual of Mental disorders (DSM-5).[1] Abnormal function in specific regions such as amygdala, prefrontal cortex, anterior cingulate cortex, hippocampus and parahippocampus, known to be related to anxiety and anxietyrelated memory, in individuals with PTSD were discovered using various neuroimaging tools.[2,3,4,5,6,7] many studies have reported altered amygdala and frontal activation in PTSD.[8,9] Shin et al.[6] have reported that PTSD patients showed amygdala hyperactivation and frontal hypoactivation, and found that these regional activities were significantly correlated with the ClinicianAdministered PTSD Scale score. Large-scale functional connectivity (FC) studies may better elucidate whole brain networks. Some functional magnetic resonance imaging (fMRI) studies have shown altered resting-state FC in some brain regions, including the amygdala, anterior cingulate cortex (ACC) and medial prefrontal cortex in patients with PTSD as compared to healthy controls (HCs).[10,11,12]

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