On Wed, 10 May 2006, David Kareken wrote:
> Thanks very much for responding. However, we just looked at that, and
> this doesn't appear to be the problem. We submitted a mask that is mostly
> 0's and 1.0s (some values ~0.6 around some edges). But, there are large
> regions in which the mask clearly has 1.0s, and which are clearly excluded
> in the analysis (i.e., in the mask.img). These also correspond to the usual
> susceptibility-prone areas.
>
> Are there other things that you or anyone on the list can think of that
> might account for this?
Hmm... I am not sure it is a problem with the explicit mask then. Only
voxels that survive ALL of the following criteria will be included in your
analysis:
- explicit mask greater zero
- all values (over time/subject) are non-zero/non-NaN
- all values (over time/subject) are greater than the mask threshold (if
specified)
- the statistics in this voxel survives the initial F-test.
Most likely you will not have data for all timepoints/subjects in the
excluded voxels.
Volkmar
--
Volkmar Glauche
-
Department of Neurology [log in to unmask]
Universitaetsklinikum Freiburg Phone 49(0)761-270-5331
Breisacher Str. 64 Fax 49(0)761-270-5416
79106 Freiburg
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