Stimulation artifact correction method for estimation of early cortico-cortical evoked potentials

Area of Science:

• Neuroscience
• Computational Neuroscience
• Biomedical Engineering

Background:

• Effective connectivity in drug-resistant focal epilepsies is studied using direct electrical stimulation and intracranial electrodes.
• Cortico-cortical evoked potentials (CCEPs) reflect signal propagation, with early components indicating direct connectivity.
• Stimulation artifacts frequently contaminate early CCEP components, hindering accurate analysis.

Purpose of the Study:

• To develop and validate a novel artifact correction method for early CCEP responses.
• To improve the analysis of direct effective connectivity in epilepsy patients.

Main Methods:

• Developed an artifact correction method based on electrical modeling of the electrode-tissue interface.
• Regressed biophysically motivated artifact templates from recorded data.
• Validated the method using simulated CCEP data and applied it to experimental data.

Main Results:

• The new method successfully distinguishes physiological CCEP responses from non-physiological artifacts.
• Demonstrated efficiency on simulated single-trial recordings, highlighting the importance of sampling frequency.
• Successfully applied the artifact correction approach to experimental patient data.

Conclusions:

• The model-based template removal method offers an improvement over averaged artifact subtraction.
• This novel correction technique enhances the analysis of early CCEP components.
• Enables more accurate inference of direct effective connectivity in future CCEP studies.