Dear experts,

we are studying amputee patients, scanned at different points in time. For each patient, we would hope (!!) to observe variations in the activation due to cortical reorganization.
Here comes the problem: we see differences in the activation maps even for the healthy hand, where we expect no major reorganization. We can lower the threshold until the maps look exactly alike, but at the same threshold the maps are quite different. The session with the smaller activation "looks" noisier, and this might account for the difference we see. This, of course, prevents us from saying anything sensible about cortical reorganization.


We understand that there is no real solution for this (oh, imaging dilemmas!), but we are wondering if there might be a way to approach the problem statistically, quantifying the noise level and correcting for it, or whatever enlightened minds can come up with.

thank you!
cristina