AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

History of AFNI updates  

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November 25, 2014 09:13AM
Hi AFNI users,

I would like to reproduce results published in Cole et al., NeuroImage 2010, in which the authors tried to identify the brain's most globally connected voxels.

The basic idea is the following: for each voxel, compute the wGBC score, which is the average of correlations of the given voxel with all other gray matter voxels. Identify as the most connected voxels those with the highest wGBC scores.

The main contribution of the paper is that it also uses statistical inference to ensure reliability across subjects. The authors employ a group ANOVA which compares each voxel's wGBC to zero and set the ANOVA threshold so that only the top 10% voxels remain.

I would like to implement a similar approach in AFNI. However, I feel that an easier approach would be the following:
1. For each subject, compute their wGBC map and convert it to z-scores (subtract mean, divide by standard deviation).
2. Run a one-sample t-test (using 3dttest++) comparing each voxel's wGBC score to zero.
3. Correct for multiple comparisons using 3dFDR.
4. Set a threshold so that only the top 10% voxels remain.

Does this approach seem sound to you?

Thanks in advance,
John



Edited 2 time(s). Last edit at 11/25/2014 09:17AM by afniuser.
Subject Author Posted

Identifying the brain's most globally connected regions

afniuser November 25, 2014 09:13AM

Re: Identifying the brain's most globally connected regions

rick reynolds November 25, 2014 04:30PM

Re: Identifying the brain's most globally connected regions

Isaac Schwabacher November 25, 2014 04:43PM

Re: Identifying the brain's most globally connected regions

afniuser November 26, 2014 05:30AM