For random effect analysis 2nd level specification using basic models, eg one sample t-test, am I correct to generate only 1 con*.img for each stimulus even with multiple sessions? And for mixed effect analysis I can generate multiple con*.img if there were multiple sessions with a particular stimulus?

And should I enter con*.img of each stimuli from all subjects into one single column, or should I enter each of them separately into multiple columns?

Thanks very much.

Yours sincerely,

Andy