Aberrant topological patterns of brain structural network in temporal lobe epilepsy

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Previous studies on temporal lobe epilepsy (TLE) brain network organization focused on cortical thickness, often excluding subcortical structures and using small sample sizes.
• Altered large-scale brain network organization is a known feature in TLE, but comprehensive analysis including subcortical regions is lacking.

Purpose of the Study:

• To investigate differences in the topological organization of whole-brain volumetric networks between patients with right TLE (RTLE) and left TLE (LTLE) with unilateral hippocampal atrophy.
• To include critical subcortical structures like the hippocampus and amygdala in the analysis of brain network organization in TLE.

Main Methods:

• Cross-sectional analysis of 86 LTLE patients, 70 RTLE patients, and 116 controls.
• Brain networks constructed from volumetric data of 80 cortical/subcortical regions using Freesurfer v5.3.
• Graph theoretical approaches applied to analyze network topology.

Main Results:

• Reduced cortical/subcortical connectivity, including the bilateral hippocampus, was observed in both TLE groups.
• Both RTLE and LTLE groups showed less optimal topological organization with decreased global efficiency and increased local efficiency.
• Hub nodes in TLE patients were concentrated in paralimbic/limbic and temporal association cortices, unlike in controls.

Conclusions:

• This study provides the first evidence of altered topological organization of the whole-brain volumetric network in TLE.
• Findings demonstrate a disruption in the coordinated patterns of cortical and subcortical morphology in TLE patients.