A 20-Channel Magnetoencephalography System Based on Optically Pumped Magnetometers

TL;DR

This paper presents a 20-channel optically pumped magnetometer-based MEG system, demonstrating its capability to measure brain magnetic fields and comparing its performance with traditional SQUID-based systems in auditory and somatosensory experiments.

Contribution

The paper introduces a novel 20-channel OPM-based MEG system and provides a direct comparison with SQUID MEG systems on human subjects.

Findings

OPM MEG system successfully measures brain magnetic fields.

Comparison shows comparable results between OPM and SQUID systems.

OPM system measures tangential magnetic field components.

Abstract

We describe a multichannel magnetoencephalography (MEG) system that uses optically pumped magnetometers (OPMs) to sense the magnetic fields of the human brain. The system consists of an array of 20 OPM channels conforming to the human subject's head, a person-sized magnetic shield containing the array and the human subject, a laser system to drive the OPM array, and various control and data acquisitions systems. We conducted two MEG experiments: auditory evoked magnetic field (AEF) and somatosensory evoked magnetic field (SEF), on three healthy male subjects, using both our OPM array and a 306-channel Elekta-Neuromag superconducting quantum interference device (SQUID) MEG system. The described OPM array measures the tangential components of the magnetic field as opposed to the radial component measured by all SQUID-based MEG systems. Herein we compare the results of the OPM- and SQUID-based MEG systems on the auditory and somatosensory data recorded in the same individuals on both systems.