Wednesday, March 12, 2014

One Weird Trick to Set P-Values in AFNI

For those new to AFNI (and even those who have been using AFNI for a while, like I have), there is a way to set a specific uncorrected voxel-wise p-value in the AFNI GUI. Simply scroll over the top or bottom area of the p-value threshold slider (i.e., around the area marked "Z-t" or "p=...q=...") and press mouse button #3 (e.g., depressing the mouse wheel for a standard PC mouse). This will bring up a window where you can enter a specific p-value, which automatically sets the slider to correspond to that value. No more guessing, no more tears.

UPDATE: It turns out that you can use any mouse button, not just mouse button #3, to get that same pop-up window.


  1. Would there be any way to do this using a trackpad on a Macbook? Thanks!

    1. Hey there,

      After you wrote that, I did some experimenting and found that you can just click on any of those areas using mouse button one, and you should see the same pop-up prompt for a p-value. I'll update the post to reflect that.