Hi,
I had an event-related design with 4 conditions. After an event, subjects
were asked to make a two-choice rating.
So, I have 4 experimental conditions and two or rather three rating
possibilities for each event (rating category 1, rating category 2 and
rating category 0 when an event was not rated cause the subjects took too
long).
Now, I would like to see how the activation in the 4 conditions will
change in dependence on the rating they made. How do I do this? I guess
parametric modulation wouldn't be appropriate because I am actually
interested to know which brain areas are activated in each rating category
(e.g., irrespective of the experimental conditions), right?! Doesn't it
rather constitute a four-by-three design?
However, now each subject yields different/unequal number of trials within
each rating categories as they, of course, didn't rate each event the
same. Likewise, sometimes a subject only had "1"-ratings or no events in
the "0" category, which means that the 4x3 design wasn't always given
either. Is this a problem for a second-level analyses? How should I handle
this?
Hope someone can help!?
If so, thanks a lot,
Nicole
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