Channel interpolation in TMS-EEG: a quantitative study towards an accurate topographical representation

Area of Science:

• Neuroscience
• Biomedical Engineering
• Signal Processing

Background:

• Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) is a key technique for investigating brain function.
• Artifacts in TMS-EEG signals can compromise the accuracy of cortical mechanism exploration.
• Accurate reconstruction of artifacted channels is essential for reliable topographical mapping and inverse problem solutions.

Purpose of the Study:

• To evaluate the performance of two different interpolation methods for artifacted TMS-EEG channels.
• To compare reconstruction accuracy between low-density (19-channel) and high-density (60-channel) EEG montages.
• To assess performance in global TMS Evoked Potential (TEP) averaging versus fixed latency analysis.

Main Methods:

• Investigated two distinct interpolation methods for artifacted TMS-EEG data.
• Utilized two datasets with differing spatial resolutions: 19-channel (low-density) and 60-channel (high-density) EEG.
• Evaluated performance across two analysis contexts: averaged TMS Evoked Potentials (TEPs) and fixed latencies (100 ms, 300 ms).

Main Results:

• The global reconstruction error was found to be lower for the high-density electrode montage.
• This improved accuracy was particularly evident at fixed latencies (100 ms and 300 ms) post-stimulation.
• The study identified differences in interpolation performance based on spatial resolution and analysis context.

Conclusions:

• High-density EEG montages provide more accurate global reconstruction of TMS-EEG signals, especially at specific latencies.
• The choice of interpolation method and analysis strategy impacts the reliability of TMS-EEG signal processing.
• Optimizing channel reconstruction is crucial for precise mapping of brain responses following TMS.