Hi all,
I found the following message in the archives:
...we would like to know whether there's an
> existing method to extract the mean percentage functional MR signal
> within a particular VOI that occurred for each task that comprised the
> contrasts.
There is no automatic facility but the percent (of whole brain signal)
activation of a voxel is easily calculated from the parameter estimates
- the variable 'beta' in working memory following a plot. These values
correspond to a VOI defined by the spatial smoothing kernel, centred
on the selected voxel.
I hope this helps - Karl
I would like to know exactly how "the percent (of whole brain signal)
activation of a voxel is easily calculated" from the numbers in the beta
images. When I followed the above instructions, I got the numbers .4097,
.3342, .4533., .1301 and 199.64. I realize the first four numbers
are parameter estimates corresponding to my four conditions. I do not
know what the last number is. Could someone give me an example equation
with these numbers that would give me the percent of whole brain signal
associated with the eg. third condition for this voxel?
thanks,
Joanna Salidis
Joanna Salidis, Ph.D
Psychology Department
Stanford University
Jordan Hall
Stanford, CA 94305
Phone: 650-725-0797
Fax: 650-725-5699
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