3dMVM: help with glfCode and gltCode

Hi,

I’m trying to run 3dMVM to see if there is significant difference between groups (G1, 2, 3, 4) in terms of neural activation during anticipation of monetary gain. I choose 3dMVM instead of 3dANOVA because we have unbalanced sample. I was wondering what is the accurate way to set up glfCode and gltCode to run F-test to test for the overall group difference, as well as post-hoc ttests to test the difference between the groups.

Below is what I had in the script:

-num_glf 1
-glfLabel 1 group -glfCode 1 ‘group : 1G1 & 1G2 & 1G3 &1G4’
-num_glt 6
-gltLabel 1 G2-G1 -gltCode 1 ‘group : 1G2 - 1G1’
-gltLabel 2 G3-G1 -gltCode 2 ‘group : 1G3 - 1G1’
-gltLabel 3 G4-G1 -gltCode 3 ‘group : 1G4 - 1G1’
-gltLabel 4 G3-G2 -gltCode 4 ‘group : 1G3 - 1G2’
-gltLabel 5 G4-G2 -gltCode 5 ‘group : 1G4 - 1G2’
-gltLabel 6 G4-G3 -gltCode 6 ‘group : 1G4 - 1G3’ \

I have tried running the script, but received an error message saying: “Inappropriate coding in test No.1!”

Best,
Tien

Tien,

Try the script again after removing the extra space after the minus sign (‘-’) in each of the following lines:

-gltLabel 1 G2-G1 -gltCode 1 ‘group : 1G2 - 1G1’ \
-gltLabel 2 G3-G1 -gltCode 2 ‘group : 1G3 - 1G1’ \
-gltLabel 3 G4-G1 -gltCode 3 ‘group : 1G4 - 1G1’ \
-gltLabel 4 G3-G2 -gltCode 4 ‘group : 1G3 - 1G2’ \
-gltLabel 5 G4-G2 -gltCode 5 ‘group : 1G4 - 1G2’ \
-gltLabel 6 G4-G3 -gltCode 6 ‘group : 1G4 - 1G3’ \

Hi Gang,

Thank you very much for your response. Removing the extra space solved the issue.

I have a related questions about glfCode in 3dLME. The -help output of 3dLME said that:

the coding


'Condition : 1*A -1*B & 1*A -1*C Emotion : 1:pos'

tests the main effect of Condition at the positive Emotion

Is this supposed to be


'Condition : 1*A -1*B & 1*A -1*C Emotion : 1*pos'

?

Because I’ve tried the coding from the -help output and get the following error message:

Error in seq.default(2, length(sepTerms), 2) :
wrong sign in ‘by’ argument
Calls: process.LME.opts → gl_Constr → glfConstr → seq → seq.default
Execution halted

Best,
Tien

Tien, thanks for pointing out the typo!