Hi,

We are attempting to run a simple paired t-test on a group of LORETA data, but get an error about time-dependent data when we try to run it. Here is the command and output:

[The-Ohio-State-University-Server:~/Desktop/LORETA] scnlab% 3dttest -set1 Linear* -set2 Log* -paired -prefix Linear_Log_ttest
++ 3dttest: AFNI version=AFNI_2008_07_18_1710 (May 26 2009) [64-bit]
3dttest: t-tests of 3D datasets, by RW Cox
*+ WARNING: NO spatial transform (neither qform nor sform), in NIfTI file 'Logsubject14CorrectedAverage_av.nii'
--- allocated 19 Megabytes memory for internal use (7 volumes)
--- starting piece 1/1 (614125 voxels) *+ WARNING: NO spatial transform (neither qform nor sform), in NIfTI file 'Logsubject14CorrectedAverage_av.nii'
** FATAL ERROR: Can't use time-dependent data: Logsubject14CorrectedAverage_av.nii
** Program compile date = May 26 2009


Also, here is the output for 3dinfo on one of the datasets:

++ 3dinfo: AFNI version=AFNI_2008_07_18_1710 (May 26 2009) [64-bit]
*+ WARNING: NO spatial transform (neither qform nor sform), in NIfTI file 'Logsubject14CorrectedAverage_av.nii'

Dataset File: Logsubject14CorrectedAverage_av.nii
Identifier Code: NII_-2wCVkpIBd4CbhXLNpHvyg Creation Date: Mon Jul 6 16:30:54 2009
Dataset Type: Echo Planar (-epan)
Byte Order: LSB_FIRST {assumed} [this CPU native = LSB_FIRST]
Storage Mode: NIFTI file
Storage Space: 2458956500 (2.5 billion) bytes
Geometry String: "MATRIX(3,0,0,0,0,3,0,0,0,0,3,0):85,85,85"
Data Axes Tilt: Plumb
Data Axes Orientation:
first (x) = Left-to-Right
second (y) = Posterior-to-Anterior
third (z) = Inferior-to-Superior [-orient LPI]
R-to-L extent: -252.000 [R] -to- 0.000 -step- 3.000 mm [ 85 voxels]
A-to-P extent: -252.000 [A] -to- 0.000 -step- 3.000 mm [ 85 voxels]
I-to-S extent: 0.000 -to- 252.000 [S] -step- 3.000 mm [ 85 voxels]
Number of time steps = 1001 Time step = 1.000s Origin = 0.000s
-- At sub-brick #0 '?' datum type is float
-- At sub-brick #1 '?' datum type is float
-- At sub-brick #2 '?' datum type is float
** For info on all 1001 sub-bricks, use '3dinfo -verb' **


Since this is data we gathered from LORETA, does that in any way change the nature of the analysis we are trying to perform? Right now we are attempting to simply compare two conditions, and we were able to do a subtraction of one condition from another, within a single subject. Any advice would be greatly appreciated.


Thank you,

-Andrew