Single pulse electrical stimulation to probe functional and pathological connectivity in epilepsy.

Area of Science:

• Neuroscience
• Neurosurgery
• Systems Neuroscience

Background:

• Single Pulse Electrical Stimulation (SPES) is an investigational tool in epilepsy surgery.
• Cortico-cortical evoked potentials (CCEPs) are measured via electrocorticogram time-locked to stimuli.
• CCEPs explore in vivo inter-areal connectivity in the human brain.

Purpose of the Study:

• To investigate the utility of SPES and CCEPs in understanding brain networks.
• To explore clinical applications in epilepsy surgery and functional brain mapping.
• To identify normal and plastic cortico-cortical connections.

Main Methods:

• Utilizing SPES at ~1Hz to elicit CCEPs from intracranial electrodes.
• Averaging electrocorticogram data time-locked to stimuli (2x20-30 trials).
• Combining SPES with 50Hz electrical cortical stimulation for functional mapping.

Main Results:

• CCEPs reveal functional brain networks like language and motor networks.
• SPES aids in mapping functional brain systems by tracking cortico-cortical connections.
• CCEPs and their variants serve as surrogate markers for epileptogenicity.

Conclusions:

• SPES and CCEPs offer a novel approach to study human brain connectivity in vivo.
• This technique has clinical applications in epilepsy surgery, brain tumor monitoring, and functional mapping.
• Standardized CCEP connectivity mapping is crucial for future connectome research.