Hi James,

So each of 30 stimulus types is presented only 6 times
for close to 3 seconds (522/180 = 2.9)? That is not a
lot of stimulus time per class. Ignoring ISI time, the
results might be a bit noisy.

If there really is 458 s of rest/fixation, those ISI
numbers of 1.4 and 6 are not too bad. More would feel
better, but results depend on the contrast between stim
classes (how large are the BOLD responses).

Adding 1.5 minutes (90 s) of fixation would add 0.5 s
to the average isi time, and probably much more to the
maximum. You would have to weigh that against the extra
scanner time, boredom, etc.

The 6*3s stimulation time is more concerning to me.

- rick