Increased interhemispheric resting-state in idiopathic generalized epilepsy with generalized tonic–clonic seizures: A resting-state fMRI study

• IGE-GTCS patients showed VMHC increases in bilateral anterior cingulate, and medial prefrontal gyrus.
• VMHC in bilateral thalamus, orbital frontal cortex, cerebellum negatively correlate with the illness duration.
• VMHC deficits and the inverse relations contribute to the understanding of pathophysiology of IGE-GTCS.

SummaryPurposeThe aim is to examine the resting state functional connectivity (RSFC) between the two hemispheres and its relationships with clinical characteristic in idiopathic generalized epilepsy with generalized tonic–clonic seizures only (IGE-GTCS) patients using a technique called “voxel-mirrored homotopic connectivity (VMHC)”.MethodsThe resting-state functional MRI (Rs-fMRI) was used to measure the RSFC in patients with IGE-GTC and age–gender matched healthy subjects. The between-group difference in interhemispheric RSFC was examined after the interhemispheric RSFC map was obtained by an automated VMHC approach.ResultsCompared to the controls, the IGE-GTCS patients showed significant increases in VMHC in the bilateral anterior cingulate and medial prefrontal gyrus. No areas showed decreased VMHC in patients. Moreover, the VMHC in bilateral thalamus, orbital frontal cortex as well as cerebellum showed significant negative correlations with the illness duration.ConclusionsThe current findings provide preliminary evidence of increased interhemispheric RSFC in patients with IGE-GTCS during the interictal period. These VMHC deficits in these regions and the inverse relations between VMHC and clinical characteristic may play an important role in the pathophysiology of IGE-GTCS. Our study may contribute to the understanding of neuro-pathophysiological mechanism of epilepsy and psychosocial function impairments in patients with IGE-GTCS.