Dear SPM users,
I would be very grateful if any of you could help me with a problem I encountered while using the Artifact Detection Toolbox (designed by Susan Whitfield-Gabrieli) on my data.
My experiment consisted of two parts: the main one (event-related design) and the localizer (block design); but scanned in one session. When checking the signal-task correlation (option in Art) I got a matrix that I am sending you as an attachment. This matrix looks the same for all participants. Namely, it seems like the brain activation is slightly negatively correlated with the task in the main experiment, but obviously positively correlated in the localizer. Could anyone tell me what could be the cause of such result?
I have an additional question about the option of the 'use diff global'. If I check this option does the program compare the mean signal between scans instead of comparing it with the first scan? What could be the cause of mean signal outliers (since I have mainly these kind of outliers)?
I thank you for your time and consideration.
Kind regards,
Marina Stosic
