Intrinsic brain network stability during kainic acid-induced epileptogenesis.

Abstract

Objective: Altered intrinsic brain networks have been revealed in patients with epilepsy and are strongly associated with network reorganization in the latent period. However, the development and reliability of intrinsic brain networks in the early period of epileptogenesis are not well understood. The current study aims to fill this gap by investigating the test-retest reliability of intrinsic brain networks in the early stage of epileptogenesis.

Methods: We used the rat intrahippocampal kainic acid model of mesial temporal lobe epilepsy. Three sessions of resting-state functional magnetic resonance imaging (rs-fMRI) data were acquired over a 2-week period from 9 sham control rats and 12 rats that later developed spontaneous epilepsy (KA). A group independent component analysis (GICA) approach was used to identify the intrinsic brain networks. Both within and between networks were identified, and test-retest reliability was assessed using the intraclass correlation coefficient (ICC).

Results: Our results showed good-to-excellent within-network stability of resting-state functional brain connectivity in most intrinsic brain networks in sham control rats and in the KA group, except for frontal cortex (FCN) and hippocampal networks (HPN). Further analysis of the between networks showed an increase in variation in the KA brain compared to the sham controls.

Significance: Overall, our study demonstrated a "moderately stable" phase of the intrinsic brain network in a 2-week latent period window, with an altered between- and within-network connectome feature.

Plain language summary: This fMRI study explored how brain connectivity changes in healthy animals compared to animals in the latent period of epilepsy. We found that functional connectivity increased during the latent period compared to the control group, and this increase persisted across all tested sessions. Additionally, brain networks became less stable in the epilepsy group, particularly in the frontal cortex and hippocampus. These observations provide further insight into how brain networks change and persist during the early stages of epileptogenesis.