We are trying to find out what would be the most appropriate nr of control subjects for our clinical fMRI experiment. We want to compare single patients data to controls (a semantic task experiment). There are 3 runs, block design. In already acquired data the activation per subject, in controls or in patients is quite large. Is it appropriate to compare 12 controls and 1 patients (a t-test) ? 

I checked Rik Henson syntax on single case, but it's not quit the response i was looking for http://www.mrc-cbu.cam.ac.uk/people/rik.henson/personal/Henson_Singlecase_06.pdf

Would be very grateful for any suggestions

Laura