"Convulsoid responses" suggesting development of autonomous epileptogenicity

Area of Science:

• Neuroscience
• Epileptology
• Computational Neuroscience

Background:

• Autonomous epileptogenicity is a key factor in seizure development.
• Identifying reliable neuronal indices for epileptogenicity is crucial for understanding seizure progression.
• Distinguishing between primary and secondary epileptogenesis requires specific biomarkers.

Purpose of the Study:

• To identify a convenient and reliable neuronal index for autonomous epileptogenicity.
• To compare changes in direct cortical responses (DCRs) during primary and projected seizure discharges.
• To investigate the development of secondary epileptogenesis.

Main Methods:

• Acute experiments were conducted on rabbits.
• Electrically induced primary (PRID) and projected seizure discharges (PROD) were used.
• Changes in DCRs at primary and mirror cortical sites were comparatively studied.

Main Results:

• In the primary site during PRID, DCRs were suppressed or disappeared, replaced by "convulsoid responses".
• In the mirror site during PROD, DCRs showed variable changes (unaffected, increased, or suppressed) without convulsoid responses.
• Independent seizure discharges in the mirror site also elicited convulsoid responses and DCR suppression.

Conclusions:

• Convulsoid responses are the most reliable indicator of autonomous epileptogenicity.
• Suppression or disappearance of DCRs serves as a supplementary sign of epileptogenicity.
• These neuronal indices can aid in the identification of secondary epileptogenesis.