Cortico-striatal synchronization in human focal seizures

Area of Science:

• Neuroscience
• Epileptology
• Systems Neuroscience

Background:

• Basal ganglia involvement in focal seizures is suggested but poorly understood.
• The precise interaction between cortical and striatal signals during seizures remains unclear.

Purpose of the Study:

• To analyze ictal striatal activity and its synchronization with the cerebral cortex using stereoelectroencephalography (SEEG).
• To investigate the role of cortico-striatal interactions in focal epilepsy pathophysiology.

Main Methods:

• Stereoelectroencephalography (SEEG) recordings in 11 drug-resistant epilepsy patients with basal ganglia electrode coverage.
• Visual inspection and non-linear correlation analysis (h2) to assess functional connectivity between cortical regions and the striatum during seizures.
• Analysis of different seizure periods: preictal, onset, and termination.

Main Results:

• Two patterns of striatal activation observed: early alpha/beta activity and late, slower theta/delta activity.
• Significant differences in cortico-striatal synchronization (h2 indices) were found during seizure onset and termination compared to background activity.
• Cortico-striatal synchronization is present from seizure onset and shows late, terminal hypersynchronization.

Conclusions:

• Cortico-striatal synchronization plays a role from the beginning of focal seizures.
• Changes in cortico-striatal synchronization may be an endogenous mechanism for seizure termination.
• The basal ganglia's role in focal epilepsy pathophysiology is more interconnected with the cortex than previously thought, suggesting potential for deep brain stimulation targets.