Hi experts,

I am using 3dMVM to see how age effect fMRI as a quantitative variable. I got results Age F from the code. But F scores are all positive. I am wondering if it possible to get a β coeffector from 3dMVM? Or some effector could show the data is increasing or decreasing with age.

Thank you.

My code:

```
3dMVM -prefix Aud_glt3 \
-bsVars "Group*Age*Risk" \
-qVars "Age,Risk" \
-num_glt 3 \
-gltLabel 1 Group -gltCode 1 'Group : 1*Singr -1*Contr' \
-gltLabel 2 GroupRisk -gltCode 2 'Group : 1*Singr -1*Contr Risk:' \
-gltLabel 3 GroupAge -gltCode 3 'Group : 1*Singr -1*Contr Age:' \
-dataTable \
Subj Group Age Sex Risk InputFile \
S002 Singr 70 1 1 S002.rs.AudSeederrts.nii'[0]'\
......
```

Gang
May 21, 2022, 8:08pm
2
You can add the following to obtain the directionality of age effecct:

-gltCode t ‘Age :’ \

Also, you need to add a space after Risk and Age on the following two lines:

-gltLabel 2 GroupRisk -gltCode 2 ‘Group : 1Singr -1 Contr Risk:’
-gltLabel 3 GroupAge -gltCode 3 ‘Group : 1Singr -1 Contr Age:’ \

Thank you Gang! I got two sub-bricks ‘Age’ and ‘Age t’. But I am wondering if I set age as a quantitive variable, how the t test runs here?

I got the exact same results after adding a space. Did I add at the right places?

```
-gltLabel 2 GroupRisk -gltCode 2 'Group : 1*Singr -1*Contr Risk: ' \
-gltLabel 3 GroupAge -gltCode 3 'Group : 1*Singr -1*Contr Age: ' \
-gltLabel 4 Age -gltCode 4 'Age :' \
```

Thank you!

Xiyue

Gang
May 23, 2022, 9:12pm
4
The following two lines

-gltLabel 2 GroupRisk -gltCode 2 'Group : 1Singr -1 Contr Risk: ’
-gltLabel 3 GroupAge -gltCode 3 'Group : 1Singr -1 Contr Age: ’ \

should change to

-gltLabel 2 GroupRisk -gltCode 2 'Group : 1Singr -1 Contr Risk : ’
-gltLabel 3 GroupAge -gltCode 3 'Group : 1Singr -1 Contr Age : ’ \

But I am wondering if I set age as a quantitive variable, how the t test runs here?

The t-test for age is for the slope or marginal effect: the amount of change in the response variable when age increases by 1.

Hi Gang,

Thank you for your reply.
I still think the results are the same in sub-bricks GroupAge and GroupAge t, including the clusters location and voxel numbers. Now my code is like this:

```
-num_glt 4 \
-gltLabel 1 Age -gltCode 1 'Age :' \
-gltLabel 2 Group -gltCode 2 'Group : 1*Singr -1*Contr' \
-gltLabel 3 GroupRisk -gltCode 3 'Group : 1*Singr -1*Contr Risk : '\
-gltLabel 4 GroupAge -gltCode 4 'Group : 1*Singr -1*Contr Age : '\
```

The t-test for age is for the slope or marginal effect: the amount of change in the response variable when age increases by 1.

If I am correct, the result of the Age t is smilar to the result of 3dRegAna -tcoef. Right?

Thank you.

Xiyue

Gang
May 25, 2022, 3:19pm
6
If I am correct, the result of the Age t is smilar to the result of 3dRegAna -tcoef. Right?

If you built the same model between 3dMVM and 3dRegAna, the result should be close to each other.