Dear SPM Experts,

   I have a question regarding using SPM5 to perform the following analysis.

For my functional PET experiment, I have three conditions (Baseline, Stimulation A, and Stimulation B) for normal controls and patients. Each human subject undergoes all three conditions, with the order of the conditions randomized to avoid any bias. In addition to look at intra-subject differences between baseline verses Stimulation A or baseline verses Stimulation B within each human subject group using paired t-test, I am also interested comparing differences between normal controls and patients for stimulation A and Stimulation B separately.

What is the best analysis (in SPM5) I can use to subtract out baseline and compare the normal and patient groups for Stimulation A and Stimulation B individually. Can you briefly describe the procedure or refer me to a document for more help?

  (Patient Stimulation A - Patient Baseline)  compared with (Normal Control Stimulation A - Normal Baseline)    ?

  (Patient Stimulation B - Patient Baseline)  compared with (Normal Control Stimulation B - Normal Baseline)    ?

Thank you so much for your time !

Sincerely,

John Xie

MD PhD candidate
Doheny Retina Institute
Biomedical Engineering
University of Southern California
Los Angeles, California, U.S.A.

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