What does meditation do to the brain?

New York Times article - "In Sitting Still a Bench Press for the Brain" by John Hanc ran on May 9 2012.  It's a short report on some basically inconclusive studies looking at the physical impacts of meditation, including one published in February, conducted by UCLA and led by Dr. Eileen Luders.

A striking finding of the study was that the degree of cortical gyrification appeared to increase as the number of years practicing meditation increased. 

“We used to believe that when you were born, your brain would grow and reach a peak in the early 20s and then start shrinking,” Dr. Luders said. “It was thought there was nothing we could do to change that.” Her research suggests that there might be. As a meditator for four years, Dr. Luders understands the degree of mental discipline involved. “People ask, ‘What do you do? Just sit there with your eyes closed?’ It’s actually hard work, because you have to make a constant mental effort.”