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Thank you very much for your help. Regards, Gelareh On Sun, Jan 23, 2011 at 1:26 AM, MCLAREN, Donald <[log in to unmask]>wrote: > Yes. > > On Saturday, January 22, 2011, Gelareh Ahmadi > <[log in to unmask]> wrote: > > > > Dear Donald, > > > > Thank you for your reply. > > > > So if I understand correctly my design is correct, just in order to show > constant linear decrease I should add contrast as below: > > > > Group EV1 EV2 EV3 EV4 EV5 > > EV6 EV7 > > subj1 subj2 time1 time 2 time 3 > > time 4 time5 > > 1 1 0 1 0 > > 0 0 0 > > 1 0 1 1 0 > > 0 0 0 > > 1 1 0 0 1 0 > > 0 0 > > 1 0 1 0 1 0 > > 0 0 > > 1 1 0 0 0 > > 1 0 0 > > 1 0 1 0 0 > > 1 0 0 > > 1 1 0 0 0 > > 0 1 0 > > 1 0 1 0 0 > > 0 1 0 > > 1 1 0 0 0 > > 0 0 1 > > 1 0 1 0 0 > > 0 0 1 > > > > Contrasts EV1 EV2 EV3 EV4 EV5 > > EV6 EV7 > > A-B 0 0 1 -1 > > 0 0 0 ( shows decrease FA between timepoint > > 1&2) > > B-C 0 0 0 1 > > -1 0 0 > > C-D 0 0 0 0 1 > > -1 0 > > D-E 0 0 0 0 > > 0 1 -1 > > A-B-C-D-E 0 0 2 1 > 0 -1 -2 > > > > Is it right? > > > > Again thank you for your kind help. > > > > Regards, > > > > Gelareh > > > > On Sat, Jan 22, 2011 at 3:41 PM, MCLAREN, Donald < > [log in to unmask]> wrote: > > > > A constant linear decrease doesn't not mean A>B>C>D>E; rather on > > average there is a constant decrease across time. If you want the > > stated equation, then you need to form a conjunction. > > > > Typically, a constant linear decrease for 5 repetitions would be > > defined as 2 1 0 -1 -2. The caveat is that this contrast could be > > driven by A and E, but it would still be considered linear across > > time. > > > > Hope this helps. > > > > 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 Thu, Jan 20, 2011 at 11:55 PM, Gelareh Ahmadi > > <[log in to unmask]> wrote: > >> Dear FSL experts, > >> > >> My question is about designing GLM for repeated measure ANOVA. > >> > >> I have FA images from DTI scans for my subjcets. Each subject scanned in > 5 different time points. > >> > >> I want to design a GLM which shows areas with decreased FA between time > point 1&2, 2&3, 3 &4 , 4&5 and also areas which shows linear decrease from > time point 1 to time point 5. > >> > >> I think for my first goal I should use ANOVA (1 factor-5 level), > therefore for instance, for 2 subjects having scan in 5 time points, in > order to show decrease FA between timepoint A&B, B&C, C&D and D&E, I should > design: > >> > >> Group EV1 EV2 EV3 EV4 EV5 > EV6 EV7 > >> subj1 subj2 time1 time 2 time 3 > time 4 time5 > >> 1 1 0 1 0 > 0 0 0 > >> 1 0 1 1 0 > 0 0 0 > >> 1 1 0 0 1 > 0 0 0 > >> 1 0 1 0 1 > 0 0 0 > >> 1 1 0 0 0 > 1 0 0 > >> 1 0 1 0 0 > 1 0 0 > >> 1 1 0 0 0 > 0 1 0 > >> 1 0 1 0 0 > 0 1 0 > >> 1 1 0 0 0 > 0 0 1 > >> 1 0 1 0 0 > 0 0 1 > >> > >> Contrasts EV1 EV2 EV3 EV4 EV5 > EV6 EV7 > >> A-B 0 0 1 -1 > 0 0 0 ( shows decrease FA between timepoint 1&2) > >> B-C 0 0 0 1 > -1 0 0 > >> C-D 0 0 0 0 > 1 -1 0 > >> D-E 0 0 0 0 > 0 1 -1 > >> > >> But I have no idea how I can show there is constant linear decrease from > time point 1 to timepoint 5 ? I mean showing that FA1>FA2>FA3>FA4>FA5. > >> > >> I would highly appreciate if any one could let me know if Iam correct > for the first goal and how I can solve my second problem. > >> > >> Best Regards, > >> > >> Gelareh > >> > > -- > > Gelareh Ahmadi, MD > > PhD Candidate > > Neuroimaging Group > > Howard Florey Institute > > University of Melbourne > > VIC, Australia, 3010 > > > > ph +61 3 8344 1904 > > fax +61 3 9347 0446 > > > > -- > > 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. > -- Gelareh Ahmadi, MD PhD Candidate Neuroimaging Group Howard Florey Institute University of Melbourne VIC, Australia, 3010 ph +61 3 8344 1904 fax +61 3 9347 0446