Decoupling of functional and structural language networks in temporal lobe epilepsy

Area of Science:

• Neuroscience
• Epilepsy Research
• Brain Imaging

Background:

• Temporal lobe epilepsy (TLE) often causes naming and word-finding deficits.
• Understanding alterations in language networks is crucial for TLE management.

Purpose of the Study:

• To identify functional and structural changes in language networks in individuals with TLE.
• To explore the relationship between white matter integrity and functional connectivity in TLE.

Main Methods:

• Functional magnetic resonance imaging (fMRI) during naming tasks in 55 TLE patients and 16 controls.
• Diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) to assess white matter pathways.
• Psychophysiological interaction (PPI) analyses for functional connectivity and regression for correlation analyses.

Main Results:

• TLE patients showed weaker functional connectivity in language networks compared to controls.
• Reduced white matter integrity (lower dispersion, higher free water) correlated with weaker functional connectivity.
• TLE patients exhibited fewer structural connections and impaired coupling between functional and structural metrics.

Conclusions:

• TLE is associated with impaired and decoupled functional and structural language networks.
• White matter damage in TLE may underlie the observed functional connectivity deficits and language dysfunction.