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Data from: Thalamus and focal to bilateral seizures: a multi-scale cognitive imaging study

Caciagli, Lorenzo1; Allen, Luke A.1; He, Xiaosong2; Trimmel, Karin1; Vos, Sjoerd B.1; Centeno, Maria1; Galovic, Marian1; Sidhu, Meneka K.1; Thompson, Pamela J.1; Bassett, Danielle S.2; Winston, Gavin P.1; Duncan, John S.1; Koepp, Matthias J.1; Sperling, Michael R.3

Published Oct 27, 2020 on Dryad. https://doi.org/10.5061/dryad.2bvq83bm8

Data files

Oct 27, 2020 version files 2.99 MB

Abstract

Objective

To investigate the functional correlates of recurrent secondarily generalized seizures in temporal lobe epilepsy (TLE), using task-based fMRI as a framework to test for epilepsy-specific network rearrangements. As the thalamus modulates propagation of temporal-lobe onset seizures and promotes cortical synchronization during cognition, we hypothesized that occurrence of secondarily generalized, i.e. focal to bilateral tonic-clonic seizures (FBTCS), would relate to thalamic dysfunction, altered connectivity and whole-brain network centrality.

Methods

FBTCS occur in a third of patients with TLE and are a major determinant of disease severity. In this cross-sectional study, we analyzed 113 patients with drug-resistant TLE (55 left/58 right), who performed a verbal fluency fMRI task that elicited robust thalamic activation. Thirty-three patients (29%) had experienced at least one FBTCS in the year preceding the investigation. We compared patients with TLE-FBTCS to those without FBTCS via a multi-scale approach, entailing analysis of SPM12-derived measures of activation, task-modulated thalamic functional connectivity (psychophysiological interaction), and graph-theoretical metrics of centrality. 

Results

Individuals with TLE-FBTCS had less task-related activation of bilateral thalamus, with left-sided emphasis, and left hippocampus than those without FBTCS. In TLE-FBTCS, we also found greater task-related thalamotemporal and thalamo-motor connectivity, and higher thalamic degree and betweenness centrality. Receiver operating characteristic curves, based on a combined thalamic functional marker, accurately discriminated individuals with and without FBTCS.

Conclusions

In TLE-FBTCS, impaired task-related thalamic recruitment coexists with enhanced thalamotemporal connectivity and whole-brain thalamic network embedding. Altered thalamic functional profiles are proposed as imaging biomarkers of active secondary generalization.