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Abstracts

Atypical Functional Connectome Hierarchy in Temporal Lobe Epilepsy

Abstract number : 2.188
Submission category : 5. Neuro Imaging / 5B. Functional Imaging
Year : 2022
Submission ID : 2204343
Source : www.aesnet.org
Presentation date : 12/4/2022 12:00:00 PM
Published date : Nov 22, 2022, 05:24 AM

Authors :
Ke Xie, Msc – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Jessica Royer, PsyD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Sara Lariviere, Msc – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Raul Rodriguez-Cruces, PhD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Reinder Vos de Wael, PhD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Bo-yong Park, PhD – Montreal Neurological Institute, McGill University; Department of Data Science, Inha University, Incheon, Republic of Korea; Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Republic of Korea; Hans Auer, Bsc – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Shahin Tavakol, Msc – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Jordan DeKraker, PhD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Yifei Weng, MD – Department of Medical Imaging, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China; Chifaou Abdallah, PhD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Lorenzo Caciagli, PhD – Department of Biomedical Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA; Andrea Bernasconi, MD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Neda Bernasconi, PhD, MD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Birgit Frauscher, PhD, MD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Zhiqiang Zhang, PhD – Department of Medical Imaging, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China; Luis Concha, PhD – Brain Connectivity Laboratory, Institute of Neurobiology, Universidad Nacional Autónoma de Mexico, Mexico; Boris Bernhardt, PhD – Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada

Rationale: Temporal lobe epilepsy (TLE), a common drug-resistant epilepsy in adults, is typically associated with hippocampal pathology. Increasing evidence suggests widespread network alterations in TLE, that extend beyond the mesiotemporal lobe.1 Here, we leverage connectome gradients, a continuous coordinate system in which confluent spatial trends of macroscale brain organization can be investigated,2 examine imbalances in functional connectome hierarchy in TLE, and probe their structural substrates.

Methods: We studied 85 individuals with drug-resistant TLE (39 males; mean±SD age = 30.7±10.5 years; 39/46 left/right-TLE) and 80 age- and sex-matched healthy controls (38 males; 31.0±8.7 years) from three independent neuroimaging sites. All participants underwent T1-weighted magnetic resonance imaging (MRI) and resting-state functional MRI (rs-fMRI) scans. We generated cortex-wide functional connectivity gradients, derived from rs-fMRI, using diffusion map embedding. Subject-specific gradients were aligned to a group-level template generated from Human Connectome Project dataset (HCP; 217 unrelated healthy individuals; 95 males; 28.5±3.7 years). Surface-based linear models compared the first two gradients in TLE relative to controls, controlling for age, sex, and site. To assess the modulatory effects of neocortical and hippocampal atrophy, group comparisons were repeated while additionally correcting for cortical thickness or ipsilateral hippocampal volume.

Results: Consistent with prior work,3 the principal gradient in healthy controls depicted smooth transitions in functional connectivity running from unimodal sensory to heteromodal association regions. Compared to controls, the first gradient showed smaller variations in TLE relative to controls, particularly revealing decreased functional differentiation of bilateral temporo-limbic cortices in TLE (pFDR < 0.05; Cohen’s d = -0.55±0.07). Stratifying findings across functional communities showed strongest gradient effects in default-mode, cingulo-opercular, and language networks (Figure 1
Neuro Imaging