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Would it be possible to include a new condition that had 1 onset for each TR (after the first 30-60s) and then include a parametric modulation for that condition? In that way I could include the regressor as a parametric? And if I did do it this way, would the addition of this new condition affect the results from any of my existing, trial-dependent conditions? Cheers, Jason On 31/07/2013 8:16 PM, MCLAREN, Donald wrote: > If you want to "ignore the entire time window" cut out that time > window - otherwise you are including it in the model. > > NaNs will break the design matrix math. > > Best Regards, Donald McLaren > ================= > D.G. McLaren, Ph.D. > Research Fellow, Department of Neurology, Massachusetts General Hospital and > Harvard Medical School > Postdoctoral Research Fellow, GRECC, Bedford VA > Website: http://www.martinos.org/~mclaren > Office: (773) 406-2464 > ===================== > This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED > HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is > intended only for the use of the individual or entity named above. If the > reader of the e-mail is not the intended recipient or the employee or agent > responsible for delivering it to the intended recipient, you are hereby > notified that you are in possession of confidential and privileged > information. Any unauthorized use, disclosure, copying or the taking of any > action in reliance on the contents of this information is strictly > prohibited and may be unlawful. If you have received this e-mail > unintentionally, please immediately notify the sender via telephone at (773) > 406-2464 or email. > > > On Wed, Jul 31, 2013 at 6:52 PM, Jason Ozubko > <[log in to unmask]> wrote: >> This is a question for the 1st level fMRI specification step. >> >> I'm trying to include some regressors into my design matrix to look for >> brain areas that modulate with certain ongoing measures. At the start of >> each session, there is 30-60s where subjects are doing a different task and >> so we have no ongoing measures for the primary task (i.e., they haven't yet >> started the primary task). I don't want to trim away the first 30-60s of >> each session because there are important trial types in that period that I >> am analyzing. >> >> So, is it possible to include regressors where SPM ignores the first 30-60s >> of those regressors? I thought that perhaps having NaN values for the >> regressors during the first 30-60s would lead SPM to ignore that time window >> but I don't know the inner workings of SPM enough to be certain it would >> work. Does anyone know if it would indeed work, or if there are any other >> ways to get SPM to ignore a regressor during certain time windows? >> >> Thanks in advance >> >> Cheers, >> Jason