Dear Jerome,
> I would like to add an additional question to the above request, though
> perhaps it's already implied in the previous message.
>
> That is, given a significant region of activation (a VOI) that emerged
> from a particular contrast, 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.
One could compute the average parameter estimates in a VOI using the
BETA???.img (or indeed con???,img) but this would have to be dome
outside SPM.
I hope this helps - Karl
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