[Mne_analysis] maxwell filtering 4D-neuroimaging/BTi data

[Denis A. Engemann]

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Hi Maria,

Is it important to run Maxfilter on your BTi data? As far as I remember the testing and adaptation to other systems than Neuromag is still in progress. Let’s see what Eric says.

And the online compensation by reference sensors of the BTi system usually does a good job in producing reasonably clean recordings.
You can also regress out explicitly the signals captured by reference channels, here the example with the HCP data.

http://mne-tools.github.io/mne-hcp/auto_tutorials/plot_reference_correction.html#sphx-glr-auto-tutorials-plot-reference-correction-py

Denis

> On 3 Dec 2018, at 08:20, Maria Hakonen <maria.hakonen at gmail.com> wrote:
> 
>         External Email - Use Caution        
> 
> Dear MNE experts,
> 
> I tried to maxwell filter meg data collected with 4D-neuroimaging/BTi system as follows:
> raw_tsss = mne.preprocessing.maxwell_filter(raw, st_only=True, ignore_ref=True,destination=trans,st_duration=60)
> 
> raw_sss = mne.preprocessing.maxwell_filter(raw, st_only=False, ignore_ref=True,destination=trans)
> 
> However, the data looks very noisy after filtering: 
> 
> Original data:
> <original.png>
> sss filtered data:
> <maxfiltered_SSS.png>
> tsss filtered data (left) and original data (right):
> <original_vs_maxfiltered.png>
> 
> I wonder if anyone knows what could be wrong?
> Is it a problem if there are discontinuities in the data (all data is not collected on the same day). 
> 
> Best,
> Maria
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