Computational NeuroscienceCleaning MEG artifacts using external cues

- External cues were used to eliminate artifacts in magnetoencephalogram (MEG) recordings.
- All methods do not reduce the rank of the data.
- The power line artifact was eliminated using a trigger time locked to the line oscillations.
- We recorded the QRS to remove the heart beat artifacts, and no ICA was required.
- We recorded the gantry vibration to reduce the artifacts produced from outside vibrations.

Using EEG, ECoG, MEG, and microelectrodes to record brain activity is prone to multiple artifacts. The main power line (mains line), video equipment, mechanical vibrations and activities outside the brain are the most common sources of artifacts. MEG amplitudes are low, and even small artifacts distort recordings. In this study, we show how these artifacts can be efficiently removed by recording external cues during MEG recordings. These external cues are subsequently used to register the precise times or spectra of the artifacts. The results indicate that these procedures preserve both the spectra and the time domain wave-shapes of the neuromagnetic signal, while successfully reducing the contribution of the artifacts to the target signals without reducing the rank of the data.