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Here is an updated link: http://www.martinos.org/~mclaren/ftp/presentations/ Best Regards, Donald McLaren ================= D.G. McLaren, Ph.D. Postdoctoral Research Fellow, GRECC, Bedford VA Research Fellow, Department of Neurology, Massachusetts General Hospital and Harvard Medical School 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 Tue, Jul 12, 2011 at 2:40 PM, MCLAREN, Donald <[log in to unmask]> wrote: > The main effect of subject doesn't exist, I'm assuming that you mean > the main effect of group. The main effect of group is invalid in both > the full and flexible factorial models (for more details see > http://www.martinos.org/~mclaren/ftp/Utilities_DGM/OHBM2011_v3.pdf). > > Your question about a similar to eye() in the full factorial is a > between-subject effect, do any of the group-condition combinations > differ from 0. This can not be done in the current models as the error > terms are wrong. You'd need to run a full/flex model for each > condition and use the eye() in that model. > > If you want the main effect of group overall, you need to average the > conditions and then use either the full or flexible factorial with > just a group factor. > > To form the interaction terms in the current model. You first need to > define them: > (g1c1-g1c2) - (g2c1-g2c2) > (g1c2-g1c3) - (g2c2-g2c3) > (g1c3-g1c4) - (g2c3-g2c4) > (g2c1-g2c2) - (g3c1-g3c2) > (g2c2-g2c3) - (g3c2-g3c3) > (g2c3-g2c4) - (g3c3-g3c4) > > Now, each row of the F-contrast will represent one of these. So you > will have 6 rows in your interaction F. It should be straight forward > to make it from the above details. The subject, group, and condition > factors will have 0s for their columns. > > Best Regards, Donald McLaren > ================= > D.G. McLaren, Ph.D. > Postdoctoral Research Fellow, GRECC, Bedford VA > Research Fellow, Department of Neurology, Massachusetts General Hospital and > Harvard Medical School > 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 Mon, Jul 11, 2011 at 12:02 PM, Stefania Benetti > <[log in to unmask]> wrote: >> Dear SPMers and experts, >> >> I am running a fMRI analysis with 4 conditions and 3 groups (g1=22,g2=17,g3=25). I am using a flexible factorial design with main effect of subject and interaction of groupXcondition. >> >> Along with the canonical contrasts, I now need to create a F contrast that reveals voxel showing some form of response that can be induced by the conditions, like the one that would be specified by using eye(12) in a full factorial design with the same conditions and groups. >> >> Is there a way to build this contrast in a flexible factorial design? >> >> Any help would be appreciated! >> >> Stefania >> >