I am conducting a 1-factor 5-levels ANOVA on 24 participants (see attachment). I have a parametric design and am interested in examining negative and positive linear as well as the negative and positive quadratic BOLD response associated with my 5 levels/conditions in a whole brain analysis. Following the f-test (which, as for as I understand, shows me all of the above mixed together), how would I go about finding regions associated with each of these separately. Also, I was planning to add differences between individuals as covariates. Is this all possible within a single higher-level glm? If not, would you be able to suggest some alternatives?