Hi Mark,

If you want to view those 4 second periods as single events, then
BLOCK(4,1) is probably what you want. Yes, the 4 is in seconds.
The stimulus times would signal the start of each 4-second event.

The alternative would be to break them into either 2 or 3 events
(2s, 2s or 2s, 1s, 1s). If you expect areas to respond to only
the choices and not the questions for some reason, then 2 or 3
events might be better.

Otherwise, viewing it as a single 4-second event should be fine.

Your last question (what to use for the stimulus times) can be
thought of as the same as the previous question. If each is one
4-second event, the times should go at the beginning. If they
were considered 2 different events, each of 2 seconds, then you
might use BLOCK(2,1) for each, where one would be at the start
of the question, and the other at the start of the options.

---

Note that if any of your stimulus durations differ (e.g. some
are of 2 seconds, some of 4) and you want to be able to compare
them (via ANOVA or a contrast), then they should be scaled so
that the durations don't matter (since a 4s BOLD response will
tend to be larger than a 2s response).

For that case, drop the second parameter (the peak of 1).

- rick