Data from: Community-informed connectomics of the thalamocortical system in generalized epilepsy

OBJECTIVE. We studied the intrinsic organization of the thalamo-cortical
circuitry in patients with generalized epilepsy with tonic-clonic seizures
(GTCS) via resting-state fMRI (rs-fMRI) connectome analysis and evaluated
its relation to drug-response. METHODS. In a prospectively-followed sample
of 41 patients and 27 healthy controls, we obtained rs-fMRI and structural
MRI. After one year of follow-up, 27 patients were classified as
seizure-free and 14 drug-resistant. We examined connectivity within and
between resting-state communities in cortical and thalamic subregions. In
addition to comparing patients to controls, we examined associations to
seizure control. We assessed reproducibility in an independent cohort of
21 patients. RESULTS. Compared to controls, patients showed a more
constrained network embedding of the thalamus, while frontocentral
neocortical regions expressed increased functional diversity. Findings
remained significant after regressing out thalamic volume and cortical
thickness, suggesting independence from structural alterations. We
observed more marked network imbalances in drug-resistant compared to
seizure-free patients. Findings were similar in the reproducibility
dataset. CONCLUSIONS. Our findings suggest a pathoconnectomic mechanism of
generalized epilepsy with generalized tonic and clonic seizures, centered
on diverging changes in cortical and thalamic connectivity. More
restricted thalamic connectivity could reflect the tendency to engage in
recursive thalamo-cortical loops, which may contribute to
hyper-excitability. Conversely, increased connectional diversity of
frontocentral networks may relay abnormal activity to an extended
bilateral territory. Network imbalances were observed shortly after
diagnosis and related to future drug-response, suggesting clinical
utility.