Hi!
I need to calculate an estimation of the % signal change of a large
number of (individual) voxels for several individual stimulus onsets
(event related design).
I tried the following procedure:
1. Slicetiming and motion correction of the functional volumes.
2. Highpass and lowpass filtering.
3. Extract a range of volumes around a single stimulus onset
(from 5 volumes before stimulus onset till 25 volumes after
stimulus offset).
4. Mask extracted functional dataset with ROI mask.
5. Run feat on the dataset (square-wave stimulus modell with onset on
the 5. volume).
As I see it, I have two possibilities now: The exact way would be to use
featquery for each voxel in my ROI (because I need the signal change in
each voxel individually and not in the ROI mask as a whole). But this
his some disadvantages for me. a) it takes a long time b) I need to
extract the signal change value from an HTML file (or are they available
somewhere else?).
Because I want to process ALL signal change values toghether with a script
I was looking for a way to get them a little easier. I tried using
tsplot for every voxel in the ROI and calculated % signal change from
the tsplot timeseries output for the full model. This works quite well,
altough it is not as exact as the previous procedure. But it still takes
some time.
Is there a faster or easier way to get the sigbal change in individual
voxels?
Thanks in advance.
Michael
--
GPG key: 1024D/3144BE0F Michael Hanke
http://apsy.gse.uni-magdeburg.de/hanke
ICQ: 48230050
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