[Mne_analysis] mne_compute_raw_inverse gave perfectly correlated source current estimates

[Kai Hwang]

Hi Alex, I changed --nave to 100 and still got perfect correlations.
Actually source estimates look identical between --nave 1 and --nave
100.
Any other suggestions?
Thanks
Kai

On Thu, Feb 23, 2012 at 2:44 AM, Alexandre Gramfort
<gramfort at nmr.mgh.harvard.edu> wrote:
> Hello Kai,
>
> a possible explanation is the "nave" used to set the regularization of
> the inverse problem.
>
> if you work with raw data, nave is 1 while with 100 epochs averaged
> it's 100 and the inverse
> solution is then far less regularized. A solution is to set the --nave
> option to a higher value in
> mne_compute_raw_inverse but you might amplify noise.
>
> hope this helps
>
> Alex
>
> On Thu, Feb 23, 2012 at 3:02 AM, Kai Hwang <kai.hwang at gmail.com> wrote:
>> Hello,
>>
>> I am trying to use mne_compute_raw_inverse to project single trial
>> epochs onto the surface. The command finishes without erros, but is
>> generating perfectly correlated source estimates from distant regions.
>> The scale and sign of current estimates differ, but the correlation is
>> either 1 or -1.
>> Below is the command:
>>
>> #do forward solution
>> mne_do_forward_solution --overwrite \
>> --meas ${s}_prep_ave.fif --subject ${s} --fwd ${s}_prep_ave_fwd.fif --meg --eeg
>>
>> #create inverse operator
>> mne_do_inverse_operator --fwd ${s}_prep_ave_fwd.fif --depth \
>> --loose 0.2 --meg --eeg --senscov ${s}_prep_cov.fif --subject ${s}
>>
>> #project raw data, for each label
>> mne_compute_raw_inverse --in ${s}_${rn}_sss_ds_raw.fif \
>> --inv ${s}_prep_ave_fwd.fif-meg-eeg-inv.fif \
>> --picknormalcomp \
>> --align_z \
>> --labeldir ./ALL-Labels \
>> --orignames \
>> --out ${s}-{rn}-label-source
>>
>> However, the same inverse operator worked fine with averaged evoked
>> data, results are reasonable when viewed in mne_analyze.
>> Any idea what could have gone wrong?
>>
>> Thanks!
>> Kai
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