Distinct effects of the basal ganglia and cerebellum on the thalamocortical pathway in idiopathic generalized epilepsy

Abstract

The aberrant thalamocortical pathways of epilepsy have been detected recently, while its underlying effects on epilepsy are still not well understood. Exploring pathoglytic changes in two important thalamocortical pathways, that is, the basal ganglia (BG)-thalamocortical and the cerebellum-thalamocortical pathways, in people with idiopathic generalized epilepsy (IGE), could deepen our understanding on the pathological mechanism of this disease. These two pathways were reconstructed and investigated in this study by combining diffusion and functional MRI. Both pathways showed connectivity changes with the perception and cognition systems in patients. Consistent functional connectivity (FC) changes were observed mainly in perception regions, revealing the aberrant integration of sensorimotor and visual information in IGE. The pathway-specific FC alterations in highorder regions give neuroimaging evidence of the neural mechanisms of cognitive impairment and epileptic activities in IGE. Abnormal functional and structural integration of cerebellum, basal ganglia and thalamus could result in an imbalance of inhibition and excitability in brain systems of IGE. This study located the regulated cortical regions of BG and cerebellum which been affected in IGE, established possible links between the neuroimaging findings and epileptic symptoms, and enriched the understanding of the regulatory effects of BG and cerebellum on epilepsy.

Reconfiguration of static and dynamic thalamo-cortical network functional connectivity of epileptic children with generalized tonic-clonic seizures

“…As expected, decreased static FC between the thalamus and cortex (frontal and temporal cortex) was observed. This result was consistent with a previous study that showed a decreased correlation in thalamo-temporopolar connection (Bernhardt et al, 2009;Gong et al, 2021). A recent review study showed that there were overlapping findings in patients with GTCS regarding deactivation in the middle/inferior temporal 10.3389/fnins.2022.953356 gyrus (Parsons et al, 2020).…”

“…Graph theory analysis of the structural covariance network of the gray matter found that children with GTCS also showed significant alterations in the nodal betweenness in the right thalamus, bilateral temporal pole, and some regions of DMN (Li et al, 2020b). These previous neuroimaging studies have provided converging evidence for both intrinsic functional connectivity (FC) and structural connectivity abnormalities of the thalamocortical network in patients with GTCS (Kim et al, 2014;Lee et al, 2014;Ji et al, 2015;Li et al, 2016;Wang et al, 2019a;Gong et al, 2021). Focus on the functional and structural changes of thalamo-cortical network would provide additional information to understand the neural mechanism of GTCS.…”

“…Specific changes in the thalamus imply that this region plays an important role in epilepsy. A recent study has detected that abnormal functional and structural integration in the cerebellum, basal ganglia, and thalamus could result in an imbalance of inhibition and excitability in the brain system of idiopathic generalized epilepsy (Gong et al, 2021). Patients with GTCS showed a more constrained network embedding of the thalamus and an increased functional diversity of the frontocentral neocortical regions (Wang et al, 2019a).…”

Impaired Functional Homotopy and Topological Properties Within the Default Mode Network of Children With Generalized Tonic-Clonic Seizures: A Resting-State fMRI Study

“…This previous study has shown that the age of the seizure onset can lead to different perturbations of network modularity and connectivity at the global and local levels in temporal lobe epilepsy, with different implications for regional plasticity and adaptive reorganization. A recent study has found that the FC between the insular and thalamic projections was significantly correlated with the onset of illness in patients with GTCS ( Gong et al, 2021 ). The onset age of illness can affect the brain network organization in patients with GTCS.…”

“…Previous studies have shown the deactivation and FC disruption of the DMN in patients with generalized seizures. For example, a previous study in idiopathic generalized epilepsy found enhanced negative FC in the precuneus of the thalamocortical pathway ( Gong et al, 2021 ). The interaction between the thalamocortical pathway and the DMN was disrupted in the generalized epilepsy.…”