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

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ziad
January 26, 2015 09:33AM
Hello Alicia,

Assuming you started off with a volume of zeros when drawing your ROI mask, then the only non-zero values should be where you drew your ROI. When you use such a volume as a mask, only non-zero voxels are considered. If all you have is the hippocampus then you would be using a smaller region than with the whole brain mask. Perhaps you are puzzled by the size of the mask dataset on disk or the grid over which the volume is defined (the number of voxels in each direction). The mask dataset size will be the same as the parent's, assuming the same storage type and no compression. The mask grid will always match that of the parent dataset in order to maintain voxel to voxel correspondance across your datasets. You can always trim a mask volume with 3dAutocrop for example, but that is not recommended when using volume masks.

cheers
Ziad
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Multiple Testing Correction in ROI

AliciaChang January 23, 2015 05:40PM

Re: Multiple Testing Correction in ROI

ziad January 26, 2015 09:33AM