Regional and remote connectivity patterns in focal extratemporal lobe epilepsy

Abstract

Background: Focal epilepsy accounts for most epilepsy cases, and frontal lobe epilepsy (FLE) accounts for the largest proportion of cases of extratemporal epilepsy syndrome. The epileptogenic zone is usually not easy to locate, contributing to a lack of imaging studies. The objective of this study was to evaluate functional connectivity patterns to explore the underlying pathological mechanisms of this disorder.Methods: Forty-three patients with focal extratemporal epilepsy [mean age ± standard deviation (SD): 29.51±8.04 years, 19 males] and the same number of healthy controls (mean age ± SD: 29.56±8.02 years, 19 males) were recruited to undergo functional magnetic resonance imaging. Mean regional homogeneity (ReHo) was measured, and regions showing significant alterations in ReHo in patients were identified to examine functional connectivity (FC). In particular, FC within the default mode network (DMN) in patients was analyzed.Results: Patients with extratemporal lobe epilepsy showed significantly higher ReHo in the bilateral precentral gyrus, and lower ReHo in frontal-cerebellum regions than healthy controls [P<0.05, Gaussian random field (GRF)-corrected]. FC analysis based on regions of interest showed significantly higher connectivity in the frontoparietal-insula region and lowered FC in the frontal-cerebellum regions (P<0.05, GRF-corrected). Altered FC within DMN was also demonstrated (P<0.05, GRF-corrected).Conclusions: Analyses of ReHo and FC based on regions of interest suggest epilepsy-related neural networks are located mainly in frontal regions in extratemporal lobe epilepsy. These findings reveal disruptions of interactions and connectivity of large-scale neural networks and frontotemporal-cerebellar regions, suggesting connectivity-based pathophysiology.

The Role of Medial Prefrontal Cortex in Acupuncture Treatment for Functional Dyspepsia

“…In the first step, the paired t -test was used to analyze the changed brain areas in 115 FD patients after acupuncture treatment and to extract the change values ( p < 0.05, GRF-corrected) ( Liu et al, 2021 ). In the second step, clinical improvement values were calculated for 115 FD patients after acupuncture treatment.…”

“…The paired t -test was used to analyze the resting-state functional connectivity (rsFC) before and after the acupuncture treatment in the higher response group. This study selected all comparison thresholds for brain regions with GRF-corrected p < 0.05 ( Liu et al, 2021 ).…”

A scoping review of the functional magnetic resonance imaging‐based functional connectivity of focal cortical dysplasia‐related epilepsy

“…43 Second, FCD-related epilepsy overall seems to be related to consistent associations with certain cortical functional networks. For example, increased connectivity in the anterior default mode network 9,39,41 and the posterior default mode network has been reported. [40][41][42] FCD-related epilepsy may also be associated with increases in connectivity in the limbic network.…”

Inherent regional brain activity changes in male obstructive sleep apnea with mild cognitive impairment: A resting-state magnetic resonance study

“…Functional connectivity (FC) is an fMRI data processing method used to explore the functional interactions between anatomically separated brain regions ( Luo et al, 2021 ). Reho and FC are considered to be complementary in examining the synchronization of local and remote brain activity ( Sun et al, 2018 ),and the simple computations and reliable representations involved have led to their use in exploring brain diseases with underlying functional alterations, such as epilepsy ( Liu et al, 2021 ), Alzheimer’s ( Ibrahim et al, 2021 ), and depression ( Chen et al, 2021 ). Biomarkers obtained by various resting-state MRI techniques [functional connectivity, Reho, amplitude of low-frequency fluctuation (ALFF)] are widely used in disease classification ( Hojjati et al, 2017 , 2019 ; Ju et al, 2019 ; Wang et al, 2021 ).…”