Modelling optically pumped magnetometer interference in MEG as a spatially homogeneous magnetic field

• DOI: 10.1016/j.neuroimage.2021.118484
• Publication Date: 2021-08-19T05:57:29Z
• Authors: Tim M. Tierney; Nicholas Alexander; Stephanie Mellor; Niall Holmes; Robert Seymour; George C. O'Neill; Eleanor A. Maguire; Gareth R. Barnes
• Keywords: SIGNAL (programming language); Magnetoencephalography

Here we propose that much of the magnetic interference observed when using optically pumped magnetometers for MEG experiments can be modeled as a spatially homogeneous field. We show this approximation reduces sensor level variance and substantially improves statistical power. This model does not require knowledge underlying neuroanatomy nor positions. It only needs information about orientation. Due to model's low rank there is little risk removing substantial neural signal. However, provide framework assess any number, design or subject neuroanatomy. find unintentionally signal reduced multi-axis recordings are performed. validated method binaural auditory evoked response paradigm demonstrated field increases SNR by factor 3. Considering simplicity efficacy, suggest correction powerful preprocessing step arrays magnetometers.