Plotting MEG epochs manually

1

Hello,

I tried to export an epoch contating a MEG recording and manually plot it in the butterfly view. However, I see that there are differences between the amplitude scales (Y-axis) and that some channels are missing in the manual plot.

I assumed that the signal values are Tesla units, and I made sure to remove the bad channels and only keep MEG channels for creating the manual plot. I am not sure if this is a montage issue or if there is something else that I am missing. I have included a picture of the two plots.

I would be greatful to have your insights.

Best

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2

I found my mistake. According to the tutorials, all the gradiometer amplitudes are scaled up with a factor of 0.04. I am including the link here:

https://neuroimage.usc.edu/brainstorm/Tutorials/TutMindNeuromag

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3

It's great to hear that you were able to solve this issue.
The units of the Magnetometers are Tesla (T), and the gradiometers are T/m.

The direct link is this one: https://neuroimage.usc.edu/brainstorm/Tutorials/TutMindNeuromag#Gradiometers_.26_magnetometers

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