Hi SPM, Because of technical issue, we are planning to stop volumes acquisition while a specific stimulus is presented ( duration 1s, 7 times during the test). we don't analyse these volumes while that specific stimulus is presented. can we do that ? or it will disrupts the temporal structure of our data ? Thank you Mar1 -- Marouane Nassim,B. Eng, Msc Tél./phone: 514-345-4931, ext. 5702 http://greta.umontreal.ca/