Evolution of MEG: a first MEG-feasible fluxgate magnetometer

Abstract

In the current article we present a first solid-state sensor feasible for magnetoencephalography (MEG), and working at room temperature. The sensor is a fluxgate magnetometer based on yttrium-iron garnet films (YIGM). In this feasibility study, we prove the concept of using the YIGM in terms of MEG by registering a simple brain-induced field: the human alpha rhythm (The data that support the findings of this study are available from the corresponding author upon reasonable request). All the experiments and results are validated with the usage of another kind of high-sensitive magnetometers - optically pumped magnetometer (OPM), which currently appears to be well-established in terms of MEG.

MaDoPO: Magnetic Detection of Positions and Orientations of Segmented Deep Brain Stimulation Electrodes: A Radiation-Free Method Based on Magnetoencephalography

“…So, the presented method for detecting the position and orientation of a directional DBS electrode using magnetic field measurements continues to appear promising. Although the accuracies achieved in our study cannot compete with currently existing methods, the method we used is radiation-free and has the potential to be significantly improved with flexible head-casts for current SQUID-MEG devices [ 33 ] or with emerging MEG measurement systems, e.g., with OPM-MEG systems using optically pumped magnetometers (OPM) [ 23 , 24 , 34 ]. Recent technological developments have resulted in cap-shaped or on-scalp MEG sensor arrays that can move with the patients’ head and adapt to the individual head shape.…”

Yttrium-iron garnet magnetometer in MEG: Advance towards multi-channel arrays

“…All the metrics presented below take into account the sensor's noise covariance matrix C. In this work we exclude all noises except the intrinsic sensor noise. Previous research in the field of yttrium-iron garnet magnetometers [40][41][42] do not demonstrate any cross-talk phenomenon, while the cross-talk of the most sensitive sensor presented in [23] will be investigated during further studies. In the current paper, since we do not have enough information about any cross-talk, we exclude it from our computations, which makes the sensors independent of each other.…”

“…However, a really big step forward in MEG evolution was done recently, in 2021, when the new type of highly-sensitive sensor had been presented and demonstrated to be feasible in terms of MEG [23]. The sensor is based on yttrium-iron garnet thin films and inherits the principle of work of a flux-gate magnetometer.…”

“…This research is motivated by completely different nature of the sensor and specifics of its geometry. The zero-generation of the YIGM is quite big in dimension (38×38×3 mm 3 ) and noisy - the level of intrinsic noise is about of [23]. The work [41] shows the possibility of decrease intrinsic noise down to (theoretical limit) and size with increase in pumping frequency.…”

Analyzing the Effect of Weak External Transcranial Magnetic Stimulation on the Primary Dominant Frequencies of Alzheimer Patients Brain by Using MEG Recordings

“…In our clinical trial, in order to estimate the atypical magnetic fields, due to abnormal neuronal activity of the AD patients' brain, we used the sensitive technique of the Tran-Medicina 2021, 57, 1164 2 of 10 scranial MagnetoEncephaloGraphy (T-MEG) [11,12]. This magnetic field of the brain is the result of the cellular ionic activity due to the dynamical alterations of the neuron membrane potentials.…”