Dear Gang,
I thank you for honing in on the source of my confusion. In my time series model for Real Picture stimuli, you say all the time points that are not specified are interpreted as Rest, whereas in fact some of those time points are Rest and others are Pseudopictures. Put another way, what is unspecified is everything that's not a Real Picture stimulus presentation, i.e., *either* Rest (=cross-bar presented onscreen) or Pseudopicture stimulus presentation. Likewise, in my time series model for Pseudopicture stimuli, the unspecified time points are those during which either a cross-bar is onscreen (Rest condition) or a real picture is presented.
Therefore I interpret the baseline to which activation for real pictures is being compared as not just Rest, but Rest + Pseudopictures. Similarly, I interpret the baseline against which activation for pseudopictures is compared to be not just Rest, but Rest + Real Pictures.
Gang, please tell me if I'm wrong and if so, why.
-Whitney