Hi,

I am still new to AFNI, but I think that I should ask about the scale for the display on the AFNI viewer. So, I have a display viewer viewing my functional images overlaid on the anatomical images. I have checked and my t-statistics range from -4.65 to 5.35. However, the "OLay" runs from -7.64777 to 7.485167. Interestingly, this is also what 3dInfo on the file says.

$ 3dinfo Imag-2sided-robust-segment-0.99.nii.gz 
++ 3dinfo: AFNI version=AFNI_16.1.01 (Apr  7 2016) [64-bit]

Dataset File:    Imag-2sided-robust-segment-0.99.nii.gz
Identifier Code: XYZ_PqdNsEpVZ7Wpf_pU0Tkywg  Creation Date: Fri Apr 10 15:42:50 2015
Template Space:  TT_N27
Dataset Type:    Func-Bucket (-fbuc)
Byte Order:      LSB_FIRST {assumed} [this CPU native = LSB_FIRST]
Storage Mode:    NIFTI
Storage Space:   435,160 (435 thousand [kilo]) bytes
Geometry String: "MATRIX(3.5,0,0,-78.75,0,3.5,0,-79.5,0,0,3.5,-63.5):46,55,43"
Data Axes Tilt:  Plumb
Data Axes Orientation:
  first  (x) = Right-to-Left
  second (y) = Anterior-to-Posterior
  third  (z) = Inferior-to-Superior   [-orient RAI]
R-to-L extent:   -78.750 [R] -to-    78.750 [L] -step-     3.500 mm [ 46 voxels]
A-to-P extent:   -79.500 [A] -to-   109.500 [P] -step-     3.500 mm [ 55 voxels]
I-to-S extent:   -63.500  -to-    83.500 [S] -step-     3.500 mm [ 43 voxels]
Number of values stored at each pixel = 1
  -- At sub-brick #0 'stim_times.1D#0_Tstat' datum type is float:     -7.64777 to       7.48517
     statcode = fitt;  statpar = 95

I can live with this for now. However, the display scale for the overlaid image has a top value of 1.000 (at the top) and -1.000 (at the bottom).

There is an autoRange which reads: autoRange: 7.64777 (a check box for the autoRange), checking which has some effect on the actual overlaid image as per the display. However, I am unclear as to what it actually does. There is also a check box for a % after that "autoRange:". Checking this has the effect of change the values of the p=.

Could someone please either point to documentation or give a summary of what exactly is going on here and how I should interpret (and manipulate) these displays?

Many thanks and best wishes,
Ranjan