Dear Bill and Tracy,
The ROI code version currently available at
http://www-psych.stanford.edu/~kalina/SPM99/Tools/roi.html
plots the average of the raw data (scaled to the session specific
grand-mean, but NOT globally scaled). The code will also perform some
preprocessing (linear detrending and band-pass filtering) if the option is
selected, as described on the webpage.
To get the raw values at every voxel within an ROI, rather than the
average across all voxels, you could look at he ROI variable that will
be present in the matlab working space after plotting. E.g.:
>> ROI
ROI =
XYZmm: [3x98 double]
XYZ: [3x98 double]
Ymad_idx: [1x98 double]
Ymad: [450x98 double]
Ymad_avg: [450x1 double]
Ypr: [450x1 double]
In this case, the ROI was 98 voxels, and the entire time series was 450
frames long. ROI.Ymad contains the raw data at every voxels of from the
roi, and ROI.Ymad_avg contains the average across the 98 voxels.
Another variable, Cond, contains the averages after trials belonging to
the same conditions have been average together.
Hope the programs can be of some use.
Best regards,
Kalina
On Sun, 24 Jun 2001, Bill Budd wrote:
> It is interesting to examine these since these values can differ
> dramatically. Some code written by Kalina Christoff is the easiest way I
> found to do this and can be downloaded from
> http://www-psych.stanford.edu/~kalina/SPM99/Tools/roi.html
> although I would be interested to know if there is some way of obtaining
> the same data (ie raw, scaled, adjusted and fitted time series) for each
> voxel within an roi rather than just the average?
>
>
>
> At 23:57 19/06/01 +0100, Tracy Robbins wrote:
> >Dear SPM Group,
> > Is there any way to plot the raw data along with adjusted and fitted data
> >for a specific voxel time series? I am not aware of any way to extract the
> >original raw voxel values. I think this may be difficult, but ideally I'd
> >like to demonstrate to people unfamiliar with fMRI how the time series
> >changes as a result of various processing operations.
> >
> >Thanks!
> > Tracy
> >
>
_____________________________________________________________________________
Kalina Christoff Email: [log in to unmask]
Office: Rm.430; (650) 725-0797
Department of Psychology Home: (408) 245-2579
Jordan Hall, Main Quad Fax: (650) 725-5699
Stanford, CA 94305-2130 http://www-psych.stanford.edu/~kalina/
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