Impaired interhemispheric synchrony and effective connectivity in right temporal lobe epilepsy

Area of Science:

• Neuroscience
• Cognitive Science
• Medical Imaging

Background:

• Brain functional networks are critical for cognitive processes.
• Cognitive impairment is a common feature of temporal lobe epilepsy (TLE).
• Right TLE (rTLE) specifically affects cognitive functions through network alterations.

Purpose of the Study:

• To investigate changes in directed functional connectivity using voxel-mirrored homotopic connectivity (VMHC) in rTLE.
• To explore the association between altered functional connectivity and cognitive impairment in rTLE.

Main Methods:

• Included 27 patients with rTLE and 27 healthy controls.
• Utilized voxel-mirrored homotopic connectivity (VMHC) and Granger causality analysis (GCA).
• Performed correlation analysis between GCA results and cognitive function scores.

Main Results:

• Decreased VMHC was observed in bilateral middle frontal gyrus, middle temporal gyrus, superior frontal gyrus (SFGdor), and supramarginal gyrus (SMG) in the rTLE group.
• Altered VMHC regions showed abnormal directed connectivity with default mode, sensorimotor, and visual networks.
• Cognitive scores (MoCA, reaction times) correlated with specific directed connectivity pathways, particularly involving MFG, SFGdor, SMG, and SMA.

Conclusions:

• Disordered functional brain networks are associated with cognitive impairment in rTLE.
• Directed functional connectivity alterations provide insights into the neurobiological basis of cognitive deficits in rTLE.