Imagine I have a block design with three conditions and no "baseline" or "rest" periods, so my model contains a regressor for each block type. For each condition 3dDeconvolve will compute a t-value and a beta. I understand (I think) that these are marginal statistics, that is each t-value represents the significance of the effect compared to the model with only that effect removed. I'm confused about the baseline against which each beta is defined in this case. Looking, for example at page 5 of [afni.nimh.nih.gov], it seems to suggest that the baseline would not include the the effects of the other two regressors. In the case like this where there is no implicit baseline, would each individual beta be relative to the model that included the combined effects of the other two regressors? I'm having some trouble reconciling these two ideas in my mind. Would the betas even be interpretable in such a case? I'd be very grateful for any help thinking about this.