In the abstract "Reduced functional connectivity between cortical sources in five meditation traditions detected with lagged coherence using EEG tomography," researchers found decreased coherence during meditation, which is interesting to me because historically so many studies seem to have shown the opposite, i.e. high coherence in meditation.
They get into some interesting speculation here:
"The globally reduced functional interdependence between brain regions in
meditation suggests that interaction between the self process functions
is minimized, and that constraints on the self process by other
processes are minimized, thereby leading to the subjective experience of
non-involvement, detachment and letting go, as well as of all-oneness
and dissolution of ego borders during meditation."