Altered communication dynamics reflect cognitive deficits in temporal lobe epilepsy.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Temporal lobe epilepsy (TLE) is a complex neurological disorder with system-level implications.
• Understanding TLE's dynamic network communication (pathoconnectomics) remains underexplored.
• Investigating the interplay between hippocampal and broader network dysfunction is crucial.

Purpose of the Study:

• To investigate abnormal network communication dynamics in TLE using computational simulations.
• To explore the influence of hippocampal and neocortical alterations on brain network dynamics.
• To assess the relationship between altered network communication and cognitive impairments in TLE.

Main Methods:

• Simulated signal spreading using a linear threshold model on structural brain graphs derived from diffusion-weighted MRI.
• Compared 31 patients with hippocampal sclerosis to 31 healthy controls.
• Evaluated the impact of hippocampal and cortical structural changes on network dynamics and correlated with cognitive data.

Main Results:

• Observed delayed information flow (slower in- and out-spreading times) across bilateral brain regions, particularly in the frontotemporal regions, thalamus, and hippocampus.
• The hippocampus significantly influenced whole-brain network dynamics, with effects diminishing when controlling for hippocampal volume.
• Slower network communication in specific brain networks (frontoparietal, limbic, default mode, subcortical) correlated with deficits in sensorimotor, executive, memory, and verbal functions.

Conclusions:

• Altered brain communication dynamics, driven by structural changes, contribute to cognitive deficits in TLE.
• This study moves beyond static network descriptions to dynamic network dysfunction in TLE.
• Highlights the critical role of the hippocampus in TLE's system-level network effects and cognitive consequences.