Regional and remote connectivity patterns in focal extratemporal lobe epilepsy

Area of Science:

• Neuroscience
• Epileptology
• Medical Imaging

Background:

• Focal epilepsy is common, with frontal lobe epilepsy (FLE) being the most frequent extratemporal form.
• Locating the epileptogenic zone in FLE is challenging, limiting imaging studies.
• Understanding pathological mechanisms requires evaluating functional connectivity patterns.

Purpose of the Study:

• To investigate functional connectivity (FC) patterns in patients with focal extratemporal epilepsy.
• To explore the underlying pathological mechanisms of FLE using neuroimaging.
• To analyze alterations in regional homogeneity (ReHo) and FC within the default mode network (DMN).

Main Methods:

• Functional magnetic resonance imaging (fMRI) was performed on 43 patients with extratemporal epilepsy and 43 healthy controls.
• Regional homogeneity (ReHo) was measured, and regions with significant ReHo alterations were identified.
• Functional connectivity (FC) was examined, with a specific focus on the default mode network (DMN).

Main Results:

• Patients exhibited higher ReHo in the bilateral precentral gyrus and lower ReHo in frontal-cerebellum regions compared to controls.
• FC analysis revealed increased connectivity in the frontoparietal-insula region and decreased FC in frontal-cerebellum regions.
• Significant alterations in FC within the default mode network (DMN) were observed in patients.

Conclusions:

• Epilepsy-related neural networks in extratemporal lobe epilepsy are primarily located in frontal regions.
• Findings indicate disrupted interactions and connectivity within large-scale neural networks, including frontotemporal-cerebellar regions.
• These disruptions suggest a pathophysiology rooted in altered neural connectivity.