I am trying to build some linear mixed models in SPSS, and am having a little trouble with the syntax - particularly with regards to the repeated measures aspects of my design.
I have around 40 participants, each of whom took part in 4 sessions: baseline, active, passive and control. I would like to find out if the relationship between my dependent variable - d-prime (behavioral performance on a task) and my independent variable - BOLD (brain activity) differs between session.
I think what I need to do first is specify a bunch of models i.e. a model with fixed slopes and intercepts, a model with random slopes and fixed intercepts and a model with random slopes and intercepts and compare the -2LL, but I'm struggling to specify these models correctly.
My data is arranged in a long format, and looks like this: