Hi Conny.
> Your suggestion to use 3 EV is my problem, as those would be linear dependent
> (because they are like time-shifted copies) and the analysis wouldn't
> work...... ( I mean, according to the paradigm I would have to use for
No - don't worry - it's not linearly dependent (ie rank deficient) at all!
> condition A = EV1 on: 10 off: 90 phase: 90
> condition B = EV2 on: 10 off: 90 phase: 40
> condition C = EV3 on: 10 off: 90 phase: 70 )
this looks perfect - and is not linearly dependent (because you have not
modelled the rest periods it's fine) - putting in phase shifts like you
have done is in this case enough to stop any rank deficiency problems.
FEAT would warn you if you did.
ttfn :)
Stephen M. Smith
Head of Image Analysis, FMRIB
Oxford University Centre for Functional MRI of the Brain
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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