Re: [Freesurfer] Talairach registration

2012-07-23 Thread Mojdeh Zamyadi
thanks Bruce :) -Mojdeh On 07/20/2012 04:27 PM, Bruce Fischl wrote: Hi Mojdeh it's really hard to say how much you should correct. In general we don't do that much. A couple of control points or a few voxels added to the wm.mgz can have a big effect if you are experienced. Mostly just

[Freesurfer] MNI to RAS

2012-07-23 Thread Jared Deck
Hi Doug, I am trying to convert MNI to RAS. I know the formula to convert from RAS to MNI is: MNI305RAS = TalXFM*Norig*inv(Torig)*[tkrR tkrA tkrS 1]' In theory, I should just be able to just invert this, but I am having difficulties because TalXFM is a non-square matrix and therefore not

[Freesurfer] Directed search for group analysis

2012-07-23 Thread Jeni Chen
Hello Freesurfer experts, I've been trying to figure out a way to run a directed search in a group analysis. I read the tutorial on ROI analysis and some of the posts here, but we can only do it with individual subject. Simply pout, I want to restrict my search areas to 4 ROIs (determined from

Re: [Freesurfer] MNI to RAS

2012-07-23 Thread Bruce Fischl
Why isn't it square? Did you add a 4th row of [0 0 0 1]? On Jul 23, 2012, at 5:28 PM, Jared Deck jm...@geneseo.edu wrote: Hi Doug, I am trying to convert MNI to RAS. I know the formula to convert from RAS to MNI is: MNI305RAS = TalXFM*Norig*inv(Torig)*[tkrR tkrA tkrS 1]' In theory, I

Re: [Freesurfer] Directed search for group analysis

2012-07-23 Thread Douglas Greve
The only difference between the mask and the label is the format of the input. The mask can take any volume format (mgh, nii, etc) and expects there to be a value at each veretx, and that value is a 0 or 1. The label is a text list of vertices to include (like lh.cortex.label). If your ROIs

Re: [Freesurfer] stats

2012-07-23 Thread Douglas Greve
Neither of these tables is the one you want. Those are tables of standard freesurfer ROIs and are unrelated to your map-based analysis. You will need to do the cluster-wise correction for multiple comparisons using the voxel-wise threshold that FDR found. Set the cwp (cluster-wise p-value)

[Freesurfer] Sample size estimates for well-powered cross-sectional cortical thickness studies

2012-07-23 Thread Heath Pardoe
Hi all, Some work my colleagues and I did investigating how many subjects should be included in a study has been recently published in Human Brain Mapping ( http://www.ncbi.nlm.nih.gov/pubmed/22807270). The paper should be freely available on pubmed central fairly soon if you don't have access to