On 12/02/2013 03:14 PM, stdp82@virgilio.it wrote:

Tank you very much.

A-Do you mean the partial correlation coeff (PCC) at each voxel averaged over region? Finally a linear regression is done between cortical thickness of a composite region and NPS. However the authors discuss every individual region as related to disease. So a table with partials correlations of individuals ROIs with NPS seems useful to support the discussion.

What did you do in the paper? The reviewer mentions a "composite region". Did you average the thickness over that region and then do the regression with NPS?

B- I'd like to obtain the covariance matrix of the regression made between cortical thickness, group and covariates. How can I do it? I'm not sure what you mean. Would this be a different matrix for each vertex? I cite the referee: "The authors must provide the covariance matrix of the regression made between cortical thickness, group and covariates as supplementary information in order to increase the value of the results."

Sorry, I don't understand what the reviewer is asking for. doug

I don't have Matlab for mri_glmfit_pcc matlab.

Stefano

----Messaggio originale---- Da: greve@nmr.mgh.harvard.edu Data: 2-dic-2013 20.47 A: freesurfer@nmr.mgh.harvard.edu Ogg: Re: [Freesurfer] Linear regression

On 12/02/2013 02:22 PM, stdp82@virgilio.it wrote:

...

Hi list,

I have some questions, please.

I performed linear regression by qdec to find the regions where the cortical thinning correlates with neuropsychological test (NPS), taking in account 3 nuisance factors.

A- I individuated some posterior regions and now I'd like to build a table with partials correlations of individuals ROIs with NPS. How can I obtain the values for each region?

Do you mean the partial correlation coeff (PCC) at each voxel averaged over region? You can get PCC maps using the mri_glmfit_pcc matlab command. You can then do the averaging over region using mri_segstats.

...

B- I'd like to obtain the covariance matrix of the regression made between cortical thickness,group and covariates. How can I do it?

I'm not sure what you mean. Would this be a different matrix for each vertex?

...

C- Is there a specific reference for qdec?

No, it is just a GLM so any GLM reference will do.

...

Thank you very much,

Stefano

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