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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bob cox
September 24, 2003 11:16AM
It is often the case that negative voxels do not replicate very well -- that is, if you have multiple imaging runs with the same paradigm in the same subject, the positive voxels will replicate pretty well, but each run will give mostly non-overlapping sets of negative voxels. If you have multiple runs, you may want to check this.

Highly repeatable negative results can be interpreted as Carl suggested. They clearly mean something. One hypothesis that I've heard put forward is that negative activations can be caused by internal speech/though that is interrupted by task performance/attention. IANANS, YMMV.

bob cox
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Subject Author Posted

negative voxel values

Krista September 23, 2003 01:13PM

Re: negative voxel values

carl September 23, 2003 01:20PM

Re: negative voxel values

bob cox September 24, 2003 11:16AM