Hi there,
I am new to FSL and MRI data analysis in general, so please excuse any errors I may make in this message and please let me know if I should provide any additional information. I am currently attempting to use Featquery to look at activation in a few ROIs during a go-no go task. Specifically in this task, I am modeling the "Correct Rejections" (when the participant correctly did NOT press a button), "False Alarms" (when the participant incorrectly pressed the button") and "Correct Rejections>False Alarms" as well as "False Alarms>Correct Rejections." I ran the Featqueries, and found that the "Correct Rejection" results seemed to come out fine, but the Featqueries I ran for the "False Alarm" contrasts all gave me nothing but zeros for the activation -- this happened every time, regardless of which ROI I was looking at. Is there any reason why this would happen in one contrast but not the others? A lab mate suggested that this may be happening because there are relatively few False Alarms (I just looked and the task included 5 runs of 75 trials, the average # of False Alarms in each trial was 5 per ppt) and there may not be enough power. That seems like a decent amount to me, though.. is this likely what's going on, or is there any other reason this may be happening? Thanks in advance,
Shannon
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