> The data that I obtained after realignment step of EPI images were
> attached.
>
> In that figure, I would like to knw abt the residual error and movement
> parameter graphs.
The residual error is a measure of how well the model fits the data at
each iteration. The plot shows that the errors decrease with each
iteration, which is what is supposed to happen.
>
> What does it actually means???What is the blue and green line indicates?
The blue and green lines represent the pitch and roll (not sure which
is which) in degrees after adjusting for the average. The x axis
represents each volume in the fMRI series. You should also have a
plot from the realignment itself, which you could compare this plot
with.
These values, plus the derivatives with respect to pitch and roll,
encode the spatial distortions that were modelled for each scan in the
series.
>
> Is the realignment step a correct one, in this case?
It seems to have done what it is supposed to do. The residual errors
decrease at each iteration.
>
> What kinda judgement I can make from these graphs?
You can see that about 3% of the variance in the data was explained by
modelling out the interaction between distortion and head motion.
This is probably much more than would be explained by the BOLD signal
that you are probably interested in. You can also see that the
residual variance decreased with each iteration, which is generally
what we would hope will happen.
You can see that the subject's head rotated by about a degree, which
is rather more than is usual in an fMRI run.
In the images, you can see the general pattern of the distortion by
head movement artifact.
> In VBM as well as SPM we do have provision to segment the TI W images. Can
> I use gray matter image obtained from VBM for SPM analysis? Or Vice versa?
VBM is just an analysis of grey matter maps from segmented anatomical
scans (not necessarily T1w) using SPM.
> Can anyone please send me the SPM script for batch processing?
There isn't a standard script. The procedures that work best for your
data are likely to differ from those that work best for the data of
others.
Best regards,
-John
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