• connectivity
• juvenile myoclonic epilepsy
• resting state-functional MRI
• voxel-based morphometry

Objectives: Juvenile myoclonic epilepsy is classified as a type of idiopathic generalized epilepsy, but converging evidence has suggested the existence of possible micro-structural alterations. We aimed to investigate alterations of thalamocortical connectivity in patients with juvenile myoclonic epilepsy using thalamic seed-based functional connectivity analysis, and their relationships with clinical characteristics.

Methods: We studied 17 patients with juvenile myoclonic epilepsy (3 males/14 females, mean age 29.9, range 21-49 years) and 13 healthy control subjects matched for age, sex and education. Patients and controls performed a 3 Tesla Magnetic Resonance Imaging scanner that included volumetric morphological sequences and an echo-planar functional magnetic resonance imaging sequence in resting conditions. Voxel-based morphometry was first performed to detect thalamic region of gray matter reduction in patients compared to controls. Between-group comparison of thalamocortical functional connectivity was then carried out using resting-state functional magnetic resonance imaging analysis seeding at thalamic region of volume difference. A series of neuropsychological tests and some clinical data (previous generalized tonic-clonic seizures, duration of disease, mono-/polytherapy) were used as covariates in intra-group connectivity analysis.

Results: Voxel based morphometry analysis detected a bilateral gray matter reduction in the anteromedial thalamus in patients with juvenile myoclonic epilepsy compared to controls. Functional connectivity analysis seeding at the anteromedial thalamus revealed a decreased thalamocortical connectivity in the right medial prefrontal cortex and precuneus/posterior cingulate cortex in patients compared to controls. We identified increased functional connectivity with bilateral frontal cortical areas in patients with previous occurrence of generalized tonic-clonic seizures and in polytherapy.

Conclusions: In patients with juvenile myoclonic epilepsy there are structural and resting state functional connectivity alterations with the anteromedial thalamus which could have potential pathophysiological and neuropsychological implications.