[Mne_analysis] Mne_analyze SNR estimate

Cushing, Cody CCUSHING1 at mgh.harvard.edu
Tue Oct 6 11:47:04 EDT 2015
Search archives:

Hi Alex,

Yes, definitely.  I'll give that a try and see what happens.  Thanks for the help!

Cheers,
Cody
________________________________________
From: mne_analysis-bounces at nmr.mgh.harvard.edu [mne_analysis-bounces at nmr.mgh.harvard.edu] on behalf of Alexandre Gramfort [alexandre.gramfort at telecom-paristech.fr]
Sent: Tuesday, October 06, 2015 11:43 AM
To: Discussion and support forum for the users of MNE Software
Subject: Re: [Mne_analysis] Mne_analyze SNR estimate

hi Cody,

to me you hit a problem I have seen a few times that the stats of the
baseline differs from the stats of the end of your epochs. As you
estimate the noise cov from baseline it generates what you describe.

A way around this I have seen working is to highpass the data and
don't do any extra baselining. The difficulty here is that you might
distort the ERP/ERF by highpass filtering.

makes sense?

Alex

On Tue, Oct 6, 2015 at 4:18 PM, Cushing, Cody <CCUSHING1 at mgh.harvard.edu> wrote:
> Hi all,
>
> This is likely a naive question, but I couldn't find much help for myself
> either in the manual or browsing the mne_analysis archives.  So, if I
> understand correctly, in mne_analyze, the SNR estimate display window shows
> what the data is expected to be with the red line and then shows the
> mismatch between the actual data and expected data with the green line (so
> the high amplitude difference between the green and red lines is bad yes?).
> Fairly unanimously, all of my subjects start off with both lines hugging
> each other pretty tight, but on some of my participants, the green line
> rises pretty sharply towards the end of the epoch.  My trial length is
> relatively long, but nothing absurd (about 1s).  My question is, what
> factors go in to computing this mismatch?  Is it something in the
> computation of the noise covariance matrix or the inverse solution that I
> can tweak parameters on to try and improve the apparent mismatch?  Or does
> this just represent subjects that aren't able to stay still and end up
> fidgeting or blinking or something towards the end of the trial?  Thanks for
> any help, and I am of course happy to supply any further info that would
> help answer my question.
>
> Cheers,
> Cody Cushing
>
> _______________________________________________
> Mne_analysis mailing list
> Mne_analysis at nmr.mgh.harvard.edu
> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/mne_analysis
>
>
> The information in this e-mail is intended only for the person to whom it is
> addressed. If you believe this e-mail was sent to you in error and the
> e-mail
> contains patient information, please contact the Partners Compliance
> HelpLine at
> http://www.partners.org/complianceline . If the e-mail was sent to you in
> error
> but does not contain patient information, please contact the sender and
> properly
> dispose of the e-mail.
>
_______________________________________________
Mne_analysis mailing list
Mne_analysis at nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/mne_analysis



More information about the Mne_analysis mailing list