Dear AFNI people,
I have behavioral mesures for each person (IQ, SEX, AGE, READING TIME) and I would like to correlate with brain activation in one condition of my task (print condition - when the subjects are reading real words). I would like to use all subjects together, not separate by group. What is the best program to use?
I used 3dTcorr1D to correlate one condition (word reading) with all behavioral measures in a 1D file (a table txt), but I don’t know if I did it right, because I couldn’t see any activation.
Can I use 3dttest++ and correlate the behavioral measures with all subjects? Which program would be better for do it?
Thank you very much,
You can use either 3dTcorr1D[/url] or [url=https://afni.nimh.nih.gov/pub/dist/doc/program_help/3dttest++.html]3dttest++ (or if you want to go super old school, 3dRegAna).
If you want to use 3dTcorr1D, you can follow instructions here.
If you’d prefer to use 3dttest++, then you can follow the instructions here.
The nuance of 3dttest++ is to then use 3dcalc to convert the t-value to a correlation via the t to R-square method.
3dcalc -a T-stat+tlrc -expr ‘(ispositive(a)-isnegative(a))*sqrt(a*a/(a*a+DF))’ -prefix corr
The two programs will provide identical results, it’s ultimately about what you’re most comfortable using. If you have a series of behavioral measures, you’ll need to do either of these processes in a loop, but you can use column selectors to grab the correct variable to correlate with the MRI data. 3dttest++ will figure out the matching data file, whereas 3dTcorr1D, the MRI and behavioral data must be in the same order.