Hi AFNI crew,

I am trying to implement an analysis in 3dLME and I would like some guidance setting up the model and random effects, and nesting.

With limited numbers of subjects, we run multiple sessions / subject. I want to nest session within subject.

I want to assess the interaction between Taste and Hydration.

I have:

5 sessions (the random effect)
3 subjects
taste: 3 levels
hydration: 2 levels

The lines I've drafted are as follows:

-model 'Subj*Taste*Hydration' \
-num_glt 5 \
-gltLabel 1 'pre-post' -gltCode 1 'Hydration : 1*pre -1*post' \
-gltLabel 2 'water_pre-post' -gltCode 2 'Hydration : 1*pre -1*post Taste : 1*H2O' \
-gltLabel 3 'sucrose_pre-post' -gltCode 3 'Hydration : 1*pre -1*post Taste : 1*Sucr' \
-gltLabel 4 'citricacid_pre-post' -gltCode 4 'Hydration : 1*pre -1*post Taste : 1*CitA' \
-gltLabel 5 'Taste_by_Hydration' -gltCode 5 'Taste : 1*H2O -1*Sucr & 1*H2O -1*CitA Hydration : 1*pre & 1*post' \
-ranEff '~1+Subj|Ssn' \
-SS_type 3 \
-dataTable
Ssn Subj Taste Hydration InputFile


1) Does the column order matter? Should the random effect be in the first column?

2) Is the correct model: 'Subj*Taste*Hydration' ?

3) Is this how to write the random effects with nesting: -ranEff '~1+Subj|Ssn' ?


Thanks!

Peter