Effect of lateralized temporal lobe epilepsy on the default mode network

Area of Science:

• Neuroscience
• Cognitive Neurology
• Epilepsy Research

Background:

• The default mode network (DMN) is crucial for resting-state cognition and includes the hippocampus.
• Temporal lobe epilepsy (TLE) is associated with cognitive and memory impairments, suggesting potential DMN involvement.

Purpose of the Study:

• To investigate alterations in the default mode network (DMN) in patients with temporal lobe epilepsy (TLE).
• To compare DMN connectivity between right TLE, left TLE, and control subjects.
• To explore the relationship between DMN changes and cognitive involvement in TLE.

Main Methods:

• Resting-state functional connectivity analysis was employed.
• Regions of interest (ROIs) were defined in the retrosplenium/precuneus (posterior DMN) and ventro-medial pre-frontal cortex (anterior DMN).
• Connectivity was assessed in 36 subjects: 11 with right TLE, 12 with left TLE, and 13 controls.

Main Results:

• Reduced connectivity between the posterior and anterior DMN was found in both right and left TLE patients.
• Individual posterior and anterior DMN components remained preserved.
• Left TLE exhibited more extensive DMN alterations compared to right TLE.

Conclusions:

• Default mode network (DMN) connectivity is disrupted in temporal lobe epilepsy (TLE).
• Lateralization of TLE influences DMN organization, with left TLE showing greater network changes.
• Observed DMN alterations may underlie cognitive and memory deficits in TLE and explain lateralized cognitive differences.