Dear SPMers:
When I use SPM to analyze the pharmacological-evoked fMRI data, I want to
add a priori model of activation due to drug into the design matrix, I want
to know if my method is correct, and how to perform t-contrast after
estimation? The process of using SPM is as follows,
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specify design or data: design
interscan interval[s]: 16
scans per session: 150
specify design in: scans
number of conditiona/trials: 2 %means base and drug
select base functions: hrf
name for condition/trial 1? base
vector of onsets - base: 1
duration: 20
name for condition/trial 2? drug
vector of onsets - drug: 21 %means inject drug at the 21st scan.
duration: 60 %just an approximate estimation
Other regressors
user specified: 1
[150] regressor 1: [input my priori model here]
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Then I performed the SPM procedures of "fMRI-data", and "Estimate".
Finally in "Results", I want to define new t-contrast to detect the actived
maps due to drug action, I just don't know how to define this t-contrast?
Does anyone can help me? or tell me if my method of add priori model is
correct? (If I don't add the priori model, usually I define t-contrast as
"-1 1" to detect the actived maps.)
Thanks,
Ping
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