We extracted volume measures from 7 ROIs in 2 groups and compared 

a) Mean of each ROI volume between group, and compared independently such as 

i) whether mean of ROI 1 in group 1 is equal to mean of ROI1 in group 2

ii)whether mean of ROI 2 in group 1 is equal to mean of ROI2 in group 2  and so on

b) Plotted the mean ROI volume for 2 independent measures and compared whether the slope between and within group is significantly different. such as

i) Slope of ROI1 is positively associated with MoCA , age (grp1) ?

ii) Slope of ROI1 is negatively associated with MoCA, age (grp2) ?

iii) Slope of ROI1 vs MoCA (grp1) is significantly different than slope of ROI1 vs MoCA (grp2) ?

iv) Slope of ROI1 vs MoCA (grp2) is significantly different than slope of ROI2 vs MoCA (grp2) ?

Q1) Do we have to perform multiple comparisons for (a) and (b)? 

Q2) If yes, do we correct across 7 measurements for (a) and 2 measurements for (b) or 7 measurements for both (a) and (b)?

There is evidence to both performing and nonperforming multiple comparisons In the literature. 

Any response (hopefully pointing to a literature) will be greatly appreciated.

Thanks

Regards

--VM