  Meditation is a family of mental practices that encompasses a wide array of
techniques employing distinctive mental strategies. We systematically reviewed
78 functional neuroimaging (fMRI and PET) studies of meditation, and used
activation likelihood estimation to meta-analyze 257 peak foci from 31
experiments involving 527 participants. We found reliably dissociable patterns
of brain activation and deactivation for four common styles of meditation
(focused attention, mantra recitation, open monitoring, and
compassion/loving-kindness), and suggestive differences for three others
(visualization, sense-withdrawal, and non-dual awareness practices). Overall,
dissociable activation patterns are congruent with the psychological and
behavioral aims of each practice. Some brain areas are recruited consistently
across multiple techniques - including insula, pre/supplementary motor
cortices, dorsal anterior cingulate cortex, and frontopolar cortex - but
convergence is the exception rather than the rule. A preliminary effect-size
meta-analysis found medium effects for both activations (d = .59) and
deactivations (d = -.74), suggesting potential practical significance. Our
meta-analysis supports the neurophysiological dissociability of meditation
practices, but also raises many methodological concerns and suggests avenues
for future research.
