Hello,
My question is why the temporal derivative does not appear in the
design matrix with the following model (using SPM99):
(simple A/B box-car design, 20 scans per condition)
interscan interval = 2
scans per session = 240
number of trials: 2 (A, B)
Stochastic Design = NO
SOA = Fixed
SOA for "A" = 40
Time to first trial for "A" = 0
SOA for "B" = 40
Time to first trial for "B" = 20
Parametric modulation = NONE
Epoch, Fixed Box-car responses
Convolve with hrf = NO
Temporal derivative = YES
Epoch lengths for both "A" and "B" = 20
interactions among trials : NO
user's specified regressors: 0
thanks,
joe
--
Best Regards,
Joseph Maldjian, MD
Assistant Professor of Radiology
Neuroradiology Section
Hospital of the University of Pennsylvania
office: (215) 349-5269
page: (215) 312-6813
fax: (215) 662-3283
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