Detection and analysis of MEG signals in occipital region with double-channel OPM sensors

Background Magnetoencephalography (MEG) has high temporal and spatial resolution and good spatial accuracy in determining the locations of source activity among most non-invasive imaging. The recently developed technology of optically-pumped magnetometer (OPM) has sensitivity comparable to that of the superconducting quantum interference device (SQUID) used in commercial MEG system. New method Double-channel OPM-MEG system detects human photic blocking of alpha rhythm at the occipital region of skull in the magnetically shielded environment via a wearable whole-cortex 3D-printed helmet. Results The alpha rhythm can be detected by the OPM-MEG system, the MEG signals are undoubtedly caused by photic blocking and similar with the results measured by SQUID magnetometer. Comparison with existing methods Due to the dependency of current commercial whole-cortex SQUID-MEG system on the liquid helium, the separation from the liquid helium space to the human head is usually at least a few centimeters. The wearable OPM-MEG system, however, can significantly improve the detection efficiency since its sensors can be mounted close to scalp, normally less than 1 cm. Conclusions OPM-MEG system successfully detects alpha rhythm blocked by light stimulation and works well in the home-made magnetically shielded environment. OPM-MEG system shows a substitute for the traditional MEG system.