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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August 30, 2019 01:52PM
Hi everyone,

After using "Clusterize" and "Rpt" buttons to generate the table of clusters, I notice that the XYZ coordinates and Z score obtained for the peak of each cluster in the table is different for the following 2 cases:
(1) Click "Jump" to move to the peak of a cluster, then observe the Z score value shown at "Thr = .. " on the bottom of the main GUI windows.
(2) I first click on "Write" to write out a dataset for the cluster, then run 3dExtrema with the cluster dataset as mask to output a few local maxima points, then I take the first point with highest Z score.
The Z score of the peak obtained from (2) is higher than that from (1).
And when moving to the XYZ coordinates obtained from (2), "Thr = .. " really shows a higher value than (1).
I feel that I am missing something important here.
Could anyone please explain the difference.
My clusters are quite small, and the difference in terms of XYZ is just a few mm (still in the same atlas ROI), but I expect the peak should be the same for (1) and (2). (!?)

Thanks,
Duong
Subject Author Posted

xyz and z-score at peak of a cluster

dlhuynh August 30, 2019 01:52PM

Re: xyz and z-score at peak of a cluster

rick reynolds September 04, 2019 09:30AM