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Dear Jo, >We understand that events do not need to synchronize with scans. Would >it be correct to assume that block onsets do not need to synchronize >with scans as well? I.e. is it possible to take some volumes which span >the change of condition thus including data for 2 blocks. Would there >be contamination between the 2 consecutive blocks of different >conditions? You are correct that block onsets do not need to synchronize with scans. As you say, this might leave you with a situation where activity from two conditions might conceivably overlap in the course of one volume of data. This is not a "problem", necessarily, but it may lead to a poorer estimation of these two conditions. An easy way around this would be to include a period between blocks that doesn't have a condition (i.e. some rest scans). >If we include slice timing in the preprocessing will SPM8 >carry out the same interpolations for the epoch onsets as the event >onsets? I'm not sure what you mean here—slicetiming is carried out on every volume that you have collected, and doesn't have anything to do with the design you use. Hope this helps! Best regards, Jonathan -- Dr. Jonathan Peelle Center for Cognitive Neuroscience and Department of Neurology University of Pennsylvania 3 West Gates 3400 Spruce Street Philadelphia, PA 19104 USA http://jonathanpeelle.net/