Hi Jon - The path.pd volumes are indeed the posterior probability distributions of each pathway. They are not normalized to a sum of 1 though b/c they're estimated by a sampling algorithm (drawing sample paths from this unknown distribution and adding up the sample paths, instead of estimating the distribution directly).
Hope this helps, a.y
On Fri, 9 Nov 2012, Jon Clayden wrote:
Dear all, I understand that the various "path.pd" image files that are created by TRACULA represent a posterior distribution over the corresponding tract location, but I was wondering if someone could explain to me exactly what the values in these images mean. I assume that they are not probabilities as such, since they have values ranging up to several hundreds.
Thanks in advance, Jon