I am try to see if RT activation on a work-memory task correlates with outside measures of cognition (different types of executive functioning) while controlling for activation related to performance on the working-memory task (n-back(2)). Is this possible? Thanks.
I know about the conflicting views on the working memory while reducing the oxygen tension in the brain. I advise you to read articles on the subject. I gave interesting article links below. All the best.
Hi Bryant,
Technically, this is possible, but not terribly easy. You'll need to model the reaction times separately from the trials in your design matrix. So, I guess you'd have three regressors, one for correct trials, one for incorrect trials (always good to separate those out, as presumably they have somewhat different component processes) and the third for reaction times, where the events should be parametrically scaled.
Your reaction time regressor will be similar/correlated to the combination of your correct/incorrect regressors (i.e. it's the same events you're modelling, just in a slightly different way) which means that it's not a terribly powerful way of modelling the effects, but sometimes you just have no choice with these things... You should then be able to define ROIs, and extract beta values/z-scores from the fMRI data/ROI, and use those to correlate with the performance of your other tasks.
If you're only interested in the RTs (not the performance of the 2-back) you could model your fMRI data with just a single regressor, parametrically scaled by RT, but that wouldn't give you such RT-specific effects (as you'd also likely get a lot of non-RT-specific activation related to the trial itself).
Hope that makes sense!
M.
Dear Bryant,
Actually, several approaches to account for RT in fMRI data were suggested. We have reviewed them in our recent paper (http://www.sciencedirect.com/science/article/pii/S0306452214006861). You could try to use one of those methods.
Best!
Aleksandra
- Badges
- Science topic
- Similar topics
- Psychology