[Mne_analysis] using inverse matrix from MNE

[Ghuman, Avniel (NIH/NIMH) [F]]

I don't actually see any reason you would want to use the same forward solution, just the same noise covariance matrix.  So, I would use mne to make a new forward solution with the second run then just use the noise covariance matrix from the first run to create an inverse solution for the second run.
________________________________________
From: Daniel G. Wakeman [dgwakeman at gmail.com]
Sent: Wednesday, May 19, 2010 8:45 PM
To: Erik B Beall
Cc: mne_analysis at nmr.mgh.harvard.edu
Subject: Re: [Mne_analysis] using inverse matrix from MNE

In this case, I believe you can use the inversion from the first run
on the second.
Simply, open the second run's average with the first runs inverse
operator ** in mne_analyze. This should work.

**You should be aware of possible mislocalizations introduced doing
this, because the person's head will not be in exactly the same
position. I would recommend at least comparing the head positions
between the two runs. If you have maxfilter available, I would
probably use this to transform the head position.

D


On 20 May 2010, at 01:02, Erik B Beall wrote:

> yes, sorry, same subject, scans acquired in adjacent scans of same
> session.
> Erik
>
> On Wed, May 19, 2010 at 7:55 PM, Daniel G. Wakeman
> <dgwakeman at gmail.com> wrote:
>> Hi Erik,
>>
>> Are these from the same participants & same recording session?
>>
>> D
>> On 20 May 2010, at 00:49, Erik B Beall wrote:
>>
>>> I have a question about using the inverse matrix computed using MEG
>>> data in MNE from a visual evoked experiment.  I have two scans, both
>>> visual evoked experiments, and I want to take the inverse matrix
>>> (and
>>> associated noise covariance matrix) computed during scan 1 and apply
>>> it to scan 2.  I don't think there is a way to do this using the
>>> compiled MNE, but I have been trying to use the matlab toolbox
>>> code to
>>> read in the matrices (forward solution, inverse matrix and noise
>>> covariance matrix) I've dumped from MNE run on scan 1.
>>>
>>> My question is, is there a way to apply the solution for scan 1 to
>>> scan 2's dataset?  Can I do this using the matlab toolbox or is
>>> there
>>> a way to do this using MNE itself?  Does anyone know of specific
>>> matlab commands from the MNE toolbox that
>>> would allow us to do this?  I had thought
>>> mne_read_inverse_operator.m
>>> was the right command to read it
>>> in, but I don't know how to use the matrix once read in.  Is there a
>>> toolbox command for
>>> applying it to the other dataset?  Thanks,
>>> Erik Beall
>>>
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>
>
>
> --
> Erik Beall
> Cleveland Clinic
> U-15-Mellen Center
> Cleveland OH, 44195-0001
> 216-445-6110
>
> ebeall at gmail.com

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