When to include ECoG electrode properties in volume conduction models.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Computational Modeling

Background:

• Implantable electrodes, like electrocorticography (ECoG) grids, are vital for recording brain activity.
• Improving spatial sensitivity in ECoG recordings necessitates a deeper understanding of electrode properties.

Purpose of the Study:

• To analyze the significance of explicitly incorporating electrodes into volume conduction calculations.
• To investigate the influence of ECoG electrode properties on recorded brain potentials.

Main Methods:

• Simulations were conducted using FEMfuns, a finite element method-based volume conduction modeling software.
• Three geometries and three distinct electrode models were employed to study electrode property influences.

Main Results:

• Electrode presence alters potential distribution based on surface impedance, source distance, and strength.
• Potentials become more uniform in tissue near electrodes compared to models without electrodes.
• Excluding detailed electrode models can lead to recorded potential changes up to a factor of three.

Conclusions:

• Electrode effects are significant when the electrode-source distance is comparable to or less than the electrode size.
• The volume conduction model must explicitly include electrode properties for accurate interpretation of ECoG measurements.
• Tissue potential distribution is affected up to a depth equivalent to the electrode's radius.