Neuromagnetism "On the Cheap": Evaluating a Combined Cylindrical Shield and Partial-Coverage OPM-MEG System for...

Area of Science:

• Biophysics
• Neuroscience
• Biomedical Engineering

Background:

• Optically pumped magnetometers (OPMs) offer advanced human neuromagnetic recording capabilities.
• Current OPM systems are costly, large, and require extensive shielding, limiting accessibility.
• This study investigates a more affordable, compact OPM system with partial head coverage.

Purpose of the Study:

• To evaluate the effectiveness of an accessible "starter" optically pumped magnetometer (OPM) system.
• To assess the system's ability to detect sensorimotor responses.
• To determine the feasibility of using a smaller, less shielded OPM setup.

Main Methods:

• Twelve participants received right-sided median nerve stimulation (MNS).
• Somatosensory-evoked fields (SEFs) and event-related (de)synchronization (ERD/ERS) in mu and beta bands were recorded.
• A compact mu-metal shield and partial sensor array were employed.

Main Results:

• Robust N20m and P60m peaks in SEFs were observed.
• Expected mu ERD and beta ERS effects were detected.
• Responses were localized to cortical generators, though signal-to-noise ratio (SNR) was lower than state-of-the-art systems.

Conclusions:

• The accessible OPM system successfully detected key neurophysiological responses.
• The system demonstrates potential for wider adoption in research settings.
• Recommendations for improving SNR and system performance are provided.