Meditation-induced bliss viewed as release from conditioned neural (thought) patterns that block reward signals in the brain pleasure center
http://www.tandfonline.com/doi/abs/10.1080/2153599X.2013.826717#.UoubJuKQMt6
The paper itself, and here, Gary Weber’s interesting blogpost about it:
http://happinessbeyondthought.blogspot.co.uk/2013/11/do-drugs-sex-competition-and-meditation.html
“Advanced practitioners experience a large increase (65%) in dopamine levels in the nucleus accumbens during meditative states.”
“meditation does not suffer from the all-too-familiar, “down-regulation” of pleasure experienced w/sex, drugs, rock&roll, money, food, etc.”
Super interesting stuff.