I Michelle,
>I have a question with regard to the "Slice timing" when acquiring the
data
>interleaved: we acquire 20 slices, so if I want to take the middle
slice as
>reference slice, which number do I have to give SPM: 19 (which is my
actual
>middle slice the 10th in acquisition) or 10?
You're right with 19 (with interleaved mode) .. you interpolate the data
of other slices from the middle *time* slice.
Don't forget to specify that before starting your statistical model ;-)
>Another question regards the function "unwarp" within the realignment
>procedure in SPM2: does it make any sense to do realign & unwarp when we
>have not acquired a field map? If we enter the parameters of movement as
>other regressors in the model afterwards, is this redundant with the
unwarp
>function or not? At the momoent, we make the realign & unwarp and
>make "coregister" and "write mean image only" (i.e. we do not reslice the
>other images) and enter the movement parameters in the statistical model
>(as "other regressors").
Well, I'm not familiar with this procedure .. but as I have understand
the unwarp function as little to do with motion .. except that motion
increases the warping. Thus, I think (but I'm not sure) that it's not so
redundant to realign and unwarp and next to enter the motion parameters
as regressors.
Best
- Cyril
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