High-frequency brain networks undergo modular breakdown during epileptic seizures

Area of Science:

• Neuroscience
• Epileptology
• Network Science

Background:

• Cortical high-frequency oscillations (HFOs) are implicated in epilepsy pathogenesis.
• Their network dynamics during seizure transitions are not well understood.

Purpose of the Study:

• Investigate high-frequency network dynamics during seizure onset and offset.
• Determine the role of HFOs in the transition from interictal to ictal states.

Main Methods:

• Applied graph theory to intracranial EEG recordings from epilepsy patients.
• Analyzed spatiotemporal evolution of community structure in high-frequency cortical networks during interictal and seizure periods.

Main Results:

• Interictal cortical networks exhibited stable community architecture.
• Seizure periods revealed a breakdown in high-frequency network community structure, forming small nodal communities across the entire network.
• Network disorganization preceded seizure onset by ~225s and persisted post-seizure for ~190s.

Conclusions:

• Modular breakdown of high-frequency cortical networks signifies a functional pathology in epileptogenesis.
• This network state indicates the highest propensity for seizure generation.