2011/12/5 Mathias Warnke <[log in to unmask]>

Hi  Experts.


I'm working on a new fMRI paradigm, and i would really appreciate any help concerned this topic.

We are trying to assess impulsiveness in risk/non-risk subjects. We have designed a 'play cards'  paradigm were  after a first 'cue' card presentation the subjects have  determine whether the next card (let's say feedback card) is higher or lower than the first one by pressing a button. We have set the same proportion between certain cue cards (2,3,4,8,9 or 10) and uncertain cue cards (5,6, or7) in a random presentation using an event related paradigm.

I have separated the analysis of 'cue' cards and the 'feedback cards' using two EV's,  setting the onsets and durations of the cards presentation. The weighting of the input was set to 1 (under  the 3 column format).

-My first question is to know whether it's ok to give the same weighting (1) to every  cue  card presentation even when they have different meaning (certain/ uncertain).
-How can I determine whether the efficency of my paradigm is ok?
-Is it ok to apply a unpaired t test to make comparissons between both groups of subjects?

Thanks in advance.

Best.