3dISC in two group of participants

AFNI Message Board
1

Hello, I am relatively new to using AFNI. I have acquired a dataset consisting of two subject groups: a group of depressed children paired with their mothers, and a control group of healthy children paired with their mothers. I am interested in using 3dISC to identify an interaction effect that demonstrates significantly reduced parent-child neural synchrony in the depressed group compared to the healthy control group. However, I am uncertain whether the 3dISC scripting is capable of implementing such an interaction analysis. Currently, I am only able to construct scripts that reveal group differences in synchrony between the depressed and control parent-child dyads. I am inquiring as to whether specifying an interaction effect in 3dISC is analogous to the contrast specification approach employed in SPM.

AFNI version info (afni -ver):

Note: G13 indicate Healthy children with their mothers, G24 means depressed children with their mothers. 
If I want to test the interaction effect similar to group(dep/HC) vs type( child-parent pair/ child-stranger pair), how do I coding in this case?

3dISC -prefix ISC2b -jobs 12                  \
		-model  '0+grp+(1|Subj1)+(1|Subj2)'     \
		-gltCode G13     '0 0 1 0 0 0 0 0 0 0'               \
		-gltCode G24     '0 0 0 0 0 0 1 0 0 0 '               \
		-gltCode G13vG24 '0 0 1 0 0 0 -1 0 0 0'              \
		Subj1	Subj2	Child	Parent	grp	grop2	grp	Group	InputFile	\
		01MDA	02MDA	sub-01MDA	sub-02MDA	G2	2	G22	DEP_C_DEP_C	/mnt/f/Step_1_ISC_NE/DEP_C_DEP_C_sub-01MDA_sub-02MDA.nii	\
		01MDA	03MDA	sub-01MDA	sub-03MDA	G2	2	G22	DEP_C_DEP_C	/mnt/f/Step_1_ISC_NE/DEP_C_DEP_C_sub-01MDA_sub-03MDA.nii	\
		01MDA	04MDA	sub-01MDA	sub-04MDA	G2	2	G22	DEP_C_DEP_C	/mnt/f/Step_1_ISC_NE/DEP_C_DEP_C_sub-01MDA_sub-04MDA.nii	\
		01MDA	06MDA	sub-01MDA	sub-06MDA	G2	2	G22	DEP_C_DEP_C	/mnt/f/Step_1_ISC_NE/DEP_C_DEP_C_sub-01MDA_sub-06MDA.nii	\
...

Many Thanks

2

How many levels does the factor grp have, and what do they represent? Also, there are two columns in the table that share the same name grp. Similarly, what do the factors grops and Group code for?

I am inquiring as to whether specifying an interaction effect in 3dISC is analogous to the contrast specification approach employed in SPM.

Could you clarify exactly what interaction you're looking for? In addition, did you compute all the pairwise ISCs---for instance, correlations between a child in the depressed group and (1) other children in the same group, (2) children in the control group, and (3) all mothers (of children in both depressed and control groups)?

Gang Chen