Magnetoencephalography based on high-Tc superconductivity: a closer look into the brain?

TL;DR

This study explores the potential of high-Tc SQUIDs in MEG to provide higher quality brain activity data by operating closer to the scalp, revealing new insights into neural rhythms.

Contribution

The paper demonstrates the feasibility of using high-Tc SQUIDs for MEG recordings and uncovers novel brain activity patterns due to their proximity to the brain.

Findings

Modulation of occipital alpha and mu rhythms detected.

High-amplitude theta-band activity observed in occipital region.

High-Tc SQUIDs can operate effectively for MEG recordings close to the scalp.

Abstract

Magnetoencephalography (MEG) enables the study of brain activity by recording the magnetic fields generated by neural currents and has become an important technique for neuroscientists in research and clinical settings. Unlike the liquid-helium cooled low-Tc superconducting quantum interference devices (SQUIDs) that have been at the heart of modern MEG systems since their invention, high-Tc SQUIDs can operate with liquid nitrogen cooling. The relaxation of thermal insulation requirements allows for a reduction in the stand-off distance between the sensor and the room-temperature environment from a few centimeters to less than a millimeter, where MEG signal strength is significantly higher. Despite this advantage, high-Tc SQUIDs have only been used for proof-of-principle MEG recordings of well-understood evoked activity. Here we show high-Tc SQUID-based MEG may be capable of providing novel information about brain activity due to the close proximity of the sensor to the head. We have performed single- and two-channel high-Tc SQUID MEG recordings of spontaneous brain activity in two healthy human subjects. We demonstrate modulation of the occipital alpha rhythm and the mu rhythm found in the motor cortex. Furthermore, we have discovered uncharacteristically high-amplitude activity in the theta-band from the occipital region of the brain. Our results suggest high-Tc SQUIDs can provide a closer look into the brain.