PowerPoint Presentation - Using AFNI Interactively

–44–

New Features of 3dDeconvolve - 2

-glt 1 contrasts/contr_AvsT.txt -glt_label 1 AvsT

-glt 1 contrasts/contr_HvsL.txt -glt_label 2 HvsL

-glt 1 contrasts/contr_ATvsHL.txt -glt_label 3 ATvsHL

• GLTs are General Linear Tests

• 3dDeconvolve provides tests for each regressor separately, but if you want to test combinations or contrasts of the b weights in each voxel, you need the -glt option

• File contrasts/contr_AvsT.txt = 0 0 0 0 0 0 0 0 1 -1 0 0 (one line with 12 numbers)

• Goal is to test a linear combination of the b weights

H In this data, we have 12 b weights: 8 baseline parameters (2 per imaging run), which are first in the b vector, and 4 regressor magnitudes, which are from -stim_file options

H This particular test contrasts the Actions and Tool bs

•tests if bActions– bTool ¹ 0

•

8 zeros