Re: [Freesurfer] Stat doubts

2013-03-21 Thread Douglas Greve
yes, no need to load rvar or the first computations of betamat and rvarmat, and you don't need beta = ... On 3/21/13 6:34 PM, Laura M. Tully wrote: So this instead? y = load('contrast/cache.th13.abs.y.ocn.dat'); X = load('Xg.dat'); beta = inv(X'*X)*X'*y; C = load('contrast/C.dat');

Re: [Freesurfer] Stat doubts

2013-03-21 Thread Laura M. Tully
So this instead? y = load('contrast/cache.th13.abs.**y.ocn.dat'); X = load('Xg.dat'); beta = inv(X'*X)*X'*y; C = load('contrast/C.dat'); rvar = MRIread('rvar.mgh'); betamat = fast_vol2mat(beta); rvarmat = fast_vol2mat(rvar); [betamat rvarmat] = fast_glmfit(y,X); rho

Re: [Freesurfer] Stat doubts

2013-03-21 Thread Douglas N Greve
oh, sorry, you'll need to recompute rvarmat (don't load rvar or beta) [betamat rvarmat] = fast_glmfit(y,X); Make sure you have $FREESURFER_HOME/fsfast/toolbox in your matlab path doug On 03/21/2013 05:04 PM, Laura M. Tully wrote: > Hi Doug, > > I gave that a try but got a matrix error - below

Re: [Freesurfer] Stat doubts

2013-03-21 Thread Laura M. Tully
Hi Doug, I gave that a try but got a matrix error - below is the command line and error output from matlab, can you spot what I'm doing wrong? (I'm a matlab newbie I'm afraid...) y = load('contrast/cache.th13.abs.y.ocn.dat'); X = load('Xg.dat'); beta = inv(X'*X)*X'*y; C = load('contrast/C.dat');

Re: [Freesurfer] Stat doubts

2013-03-21 Thread Douglas N Greve
It does it across the whole brain (on a voxel-by-voxel basis) but it is specific to the contrasts that you specify. You can run the same commands on the cluster averaged data (xxx.y.ocn...). To do this, don't load in the beta file. Instead y = load('xxx.y.ocn...'); beta = inv(X'*X)*X'*y; then p

Re: [Freesurfer] Stat doubts

2013-03-21 Thread Douglas N Greve
On 03/21/2013 01:37 PM, Gabriel Gonzalez Escamilla wrote: > Thanks Doug for your quick answer, > > Sorry for so late answer. > > One question about this, is about the fast_vol2mat, is this a > function? if so, where can I get it? $FREESURFER_HOME/fsfast/toolbox > > As the PCC is the R value, I'm

Re: [Freesurfer] Stat doubts

2013-03-21 Thread Laura M. Tully
I had this exact question yesterday :-) The functions necessary to run it are in $FREESURFER_HOME/matlab and $FREESURFER_HOME/fsfast/**toolbox Just add the path to these directories in your matlab (file -> setpath) and you can run the function from your matlab command window *Doug -* I had a follo

Re: [Freesurfer] Stat doubts

2013-03-21 Thread Gabriel Gonzalez Escamilla
Thanks Doug for your quick answer, Sorry for so late answer.One question about this, is about the fast_vol2mat, is this a function? if so, where can I get it?As the PCC is the R value, I'm guessing that I can just square at it, to obtain R2.When you asked me to divide the beta by sqrt(rvar), is

Re: [Freesurfer] Stat doubts

2013-03-14 Thread Douglas Greve
Hi Gabriel, I've attached a matlab routine which will compute the PCC. If you cd into the GLM dir, then X = load('Xg.dat'); beta = MRIread('beta.mgh'); C = load('yourcontrast/C.dat'); rvar = MRIread('rvar.mgh'); betamat = fast_vol2mat(beta); rvarmat = fast_vol2mat(rvar); rhomat = fast_glm_pcc(

[Freesurfer] Stat doubts

2013-03-14 Thread Gabriel Gonzalez Escamilla
Dear Freesurfers I'm performing regression analyses including confounding variables, and I would like to know how to obtain the following information:A) The squre Rand B) The standarized beta coefficient of an independient variable; and the partial correlation with its p-valuesMany thanks in advanc