Hongchuan Zhang wrote:
> Hi, list, > I am new to optseq2 so I really need advices to my questions. We have > an experiment of 2 factors with36 trials for each factor, and another > 24 null trials. So in total we have 96 trials. We also have 3 random > jitters which make our trials could last for either 4.6, 5 or 5.4 > seconds. The total session time is thus 480 seconds. Since our TR is 2 > seconds, the ntp = 240. > My questions are: > (1) How can I set the psdwin? My intuition is that dPSD should be > divided by both TR and trial duration. That means we can only have a > dPSD = 0.2. Would that be too small? I observed that by doing this the > largest psdmaxis only 2 seconds. That is not too small, but if you are going to analyze your data with an FIR model, then it will kill your power. If you are going to assume a shape (eg, gamma function or diff of gammas), then it is fine. > (2) What should I do if I want to break the session into two parts? > The previous optseq version seems to allow one specify the runs for > each sesssion. But I did not find this option in optseq2. Can I just > use half the trials to get two sequences and use themfor thetwo parts? Yes, spec --nkeep 2 doug > Thanks! Your suggestionis appreciated. > Hongchuan > 2008-11-03 > ------------------------------------------------------------------------ > Hongchuan Zhang, Ph.D. > Postdoctoral Research Associate > Developmental Cognitive Neuroscience Laboratory > Northwestern University > 2240 North Campus Drive > Frances Searle Building, Room 2-356 > Evanston, Illinois, 60208 > phone: (847)467-1549 > e-mail: hongchuan-zhang at northwestern.edu > >------------------------------------------------------------------------ > >_______________________________________________ >Freesurfer mailing list >Freesurfer@nmr.mgh.harvard.edu >https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > -- Douglas N. Greve, Ph.D. MGH-NMR Center [EMAIL PROTECTED] Phone Number: 617-724-2358 Fax: 617-726-7422 In order to help us help you, please follow the steps in: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting
_______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
