Hi Woogul,
Then you might want the 3dcalc -expr to be 'step(c) * min(200, a/b*100)'.
The 'step()' function will not end up multiplying by 0.3333, say, at the
edges of the mask.
I guess there was no -concat option used at the time that you gave the
regressor maximums.
So at this point you are satisfied with the precuneus beta values, yes?
Atlas ROIs may be better for you because they are independent of the
stimuli. Comparing 'a' betas across areas that were statistically
significant might start to get you in trouble. But I'll let others
answer that statistical question.
- rick