Mapping the Meditative Mind is a presentation from the 2013 Buddhist Geeks Conference. David Vago of Harvard Medical School talks about some of the latest findings in contemplative neuroscience, along with Shinzen Young. Video is next to last on the page.
The changes in brain activity for advanced meditators are sometimes massive. For example, a 60% increase in areas of the frontopolar cortex, in a field where changes of perhaps 0.5-1.0 % are often considered significant.
One interesting finding, although the sample was small, was that the decrease in posterior cingulate cortex (PCC) activation (seen in Brewer's work, for example) was confounded by two meditators with the most formal practice who I believe showed increases, although I think this may be change from baseline as opposed to absolute values.
I also thought it interesting that Shinzen's maps, which in this presentation were based on the hearing-seeing-somatic axes, did not include thought.