Brain mapping 1 Channel arrays 1 Gradiometer 1 Iron 1 MEG 1 Magnetoencephalography 1 Magnetometer sensors 1 Magnetometers 1 Multi channel 1 Noise levels 1 OPMs 1 Optically pumped 1 Optically pumped magnetometer 1 SNR 1 SQUID 1 SQUIDs 1 Shellfish 1 Signal to noise ratio 1 Simulation 1 YIGM 1 Yttrium iron garnet 1 Yttrium iron garnets 1 Yttrium-iron garnet magnetometer gradiometers 1 magnetometers 1 simulation 1