Hi CONN folk,

Some advice please on a nuisance covariate (age) in a paired T-test.

For a cohort of subjects we acquired two task fMRI runs, each run acquired on the same day (different subjects on different days). In CONN we have two sessions, one each for run1 and run2. In RESULTS (2nd level) the default 'Conditions' contrast of [1 -1] gives us paired t-rest results. We have used both seed-based and group ICA designs.

I'm concerned about discounting the effect of age. Clearly, for each subject the age associated with each run is the same. Should I account for different ages across the cohort?

I have loaded Age via SETUP: Covariates (2nd-level) and it appears in RESULTS Subject Effects beneath 'AllSubjects'.

We have selected 'AllSubjects' and ‘Age’ and set the contrast to [1 0], (and left Conditions contrast [1 -1]).

Is this correct? It makes quite a difference to not discounting for age!

Leighton