Hello all,
I am having a problem with voxels being masked out of my analysis due to lower signal. I have some extra equipment inside the scanner which causes a bit of increased signal loss. However, when I look at my actual functional data (preprocessed or not preprocessed), the signal loss is not that severe.
I am running a fairly standard HRF analysis, with implicit masking off and no mask specified. I'm loosing a LOT of data from signal loss, in the usual regions (anterior temporal and medial frontal). When I load the Beta or contrast images, there is simply no data in those regions. But looking at the raw data, their appears to be enough signal for a reasonable analysis. The signal loss in some cases even extends into the hippocampus and medial temporal structures, which seems very excessive to me.
I wan to force SPM to do statistics on those voxels. I can see no option at present to allow such a thing. Is there any way for me to force SPM to calculate statistics for those regions, and not engage in this (unasked for) implicit masking?
Thanks for the help.
Colin.
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