Large‐scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Abstract

Mesial temporal lobe epilepsy (MTLE) with hippocampus sclerosis (HS) is associated with functional and structural alterations extending beyond the temporal regions and abnormal pattern of brain resting state networks (RSNs) connectivity. We hypothesized that the interaction of large‐scale RSNs is differently affected in patients with right‐ and left‐MTLE with HS compared to controls. We aimed to determine and characterize these alterations through the analysis of 12 RSNs, functionally parceled in 70 regions of interest (ROIs), from resting‐state functional‐MRIs of 99 subjects (52 controls, 26 right‐ and 21 left‐MTLE patients with HS). Image preprocessing and statistical analysis were performed using UF2C‐toolbox, which provided ROI‐wise results for intranetwork and internetwork connectivity. Intranetwork abnormalities were observed in the dorsal default mode network (DMN) in both groups of patients and in the posterior salience network in right‐MTLE. Both groups showed abnormal correlation between the dorsal‐DMN and the posterior salience, as well as between the dorsal‐DMN and the executive‐control network. Patients with left‐MTLE also showed reduced correlation between the dorsal‐DMN and visuospatial network and increased correlation between bilateral thalamus and the posterior salience network. The ipsilateral hippocampus stood out as a central area of abnormalities. Alterations on left‐MTLE expressed a low cluster coefficient, whereas the altered connections on right‐MTLE showed low cluster coefficient in the DMN but high in the posterior salience regions. Both right‐ and left‐MTLE patients with HS have widespread abnormal interactions of large‐scale brain networks; however, all parameters evaluated indicate that left‐MTLE has a more intricate bihemispheric dysfunction compared to right‐MTLE. Hum Brain Mapp 37:3137–3152, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Anxiety and depression symptoms disrupt resting state connectivity in patients with genetic generalized epilepsies

“…To investigate the influence of combined anxiety and depression on multiple resting state networks (internetwork and intranetwork analysis) we used UF2C toolbox (http://www.lniunicamp.com/uf2c), running on MATLAB/SPM12 as previously described in . In summary, the preprocessing was based on functional MRI (fMRI) dynamic realignment (using mean image as reference), image coregistration (fMRI mean image with T1‐weighted image), spatial normalization (Montreal Neurological Institute [MNI]‐152), smoothing (kernel of 6 × 6 × 6 mm 3 full width at half maximum), T1‐weighted image tissue segmentation (gray matter [GM], white matter [WM], and cerebral spinal fluid [CSF]), and normalization (MNI‐152).…”

Default Mode Network Disruption in Stroke-Free Patients with Atrial Fibrillation

“…fMRI images were analyzed using SPM12 (Statistical Parametric Mapping 12, http://www.fil.ion.ucl.ac.uk/spm/) and UF 2 C -User-friendly Functional Connectivity toolbox (http://www.lni.hc.unicamp.br/app/uf2c/), a free tool that standardizes connectivity studies [21]. …”

“…fMRI preprocess was performed according to the UF 2 C standard approach [21]. It included fMRI dynamics realignment, coregistration of volumetric T1-weighted image and EPI mean volume of each subject, segmentation of T1-weighted image in gray and white matter and cerebrospinal fluid, spatial normalization to MNI-152 space of both images, and EPIs smoothing (6 × 6 × 6 mm 3 full width at half maximum).…”

Resting‐state functional brain networks in adults with a new diagnosis of focal epilepsy

“…Blood-oxygen-level-dependent (BOLD) signal from the cerebral white matter and ventricles was removed prior to seed-based connectivity analysis using principal component analysis of the multivariate BOLD signal within each these masks obtained from the segmented T1weighted MPRAGE scans (Fallon et al, 2016;Woodward, Rogers, & Heckers, 2011). These networks were chosen as they have been intimately associated with aspects of cognitive functioning disrupted in NDfE (Aikia et al, 1995(Aikia et al, , 2001Ichesco et al, 2012;Kalviainen et al, 1992;Markett et al, 2014;Menon, 2015;Prevey et al, 1998;Pulliainen et al, 2000;Schmidt et al, 2016;Taylor et al, 2010) and/or have been demonstrated to be significantly altered in refractory epilepsy (de Campos et al, 2016;Kay et al, 2013;Wei et al, 2015). We generated seed-to-voxel connectivity maps for each individual for the following reproducibly demonstrated functional networks: the default mode, salience, fronto-parietal attention, language, and sensorimotor networks.…”

“…These neuroimaging approaches have provided significant insights into cognitive dysfunction in people with neurological, neurodegenerative, and neuropsychiatric disorders (Cataldi, Avoli, & Villers-Sidani, 2013;Li et al, 2015;Woodward & Cascio, 2015). Alterations in these three functional networks have been reported in patients with chronic temporal lobe epilepsy and idiopathic generalized epilepsy (de Campos, Coan, Lin Yasuda, Casseb, & Cendes, 2016;Kay et al, 2013;Wei et al, 2015), and such alterations have been inferred to underlie cognitive impairment in (Fisher et al, 2017)); FSAI, focal seizure awareness impaired (formerly complex partial seizure (Fisher et al, 2017)); FTBTC, focal to bilateral tonic-clonic (formerly generalized tonic-clonic seizure (Fisher et al, 2017) There were two primary objectives of the present study. Alterations in these three functional networks have been reported in patients with chronic temporal lobe epilepsy and idiopathic generalized epilepsy (de Campos, Coan, Lin Yasuda, Casseb, & Cendes, 2016;Kay et al, 2013;Wei et al, 2015), and such alterations have been inferred to underlie cognitive impairment in (Fisher et al, 2017)); FSAI, focal seizure awareness impaired (formerly complex partial seizure (Fisher et al, 2017)); FTBTC, focal to bilateral tonic-clonic (formerly generalized tonic-clonic seizure (Fisher et al, 2017) There were two primary objectives of the present study.…”