Dr. Giuseppe Pagnoni, assistant professor of psychiatry and behavioral sciences, has revealed that the study involved the use of functional magnetic resonance imaging (fMRI) to examine changes in blood flow in the brain, as the subjects meditating were interrupted by stimuli designed to mimic the appearance of spontaneous thoughts.
Writing about their findings in the online edition of the journal Public Library of Science One, the researchers said that after being interrupted by a word-recognition task, experienced meditators' brains returned faster to their pre-interruption condition.
The study compared 12 people from the Atlanta area with more than three years of daily practice in Zen meditation with 12 others who had never practiced meditation.
The researchers asked the subjects to focus on their breathing while scanning their brains.
Every once in a while, they had to distinguish a real word from a nonsense word presented at random intervals on a computer screen and, having done that, promptly "let go" of the just processed stimulus by refocusing on their breath.
It was observed that differences in brain activity between experienced meditators and novices after interruption could be seen in a set of areas often referred to as the "default mode network".
The researchers said that, after interruption, experienced meditators were able to bring activity in most regions of the default network back to baseline faster than non-meditators.
The effect was especially prominent in the angular gyrus, a region important for processing language, they added.
"This suggests that the regular practice of meditation may enhance the capacity to limit the influence of distracting thoughts. This skill could be important in conditions such as attention deficit and hyperactivity disorder, obsessive-compulsive disorder, anxiety disorder and major depression, characterized by excessive rumination or an abnormal production of task-unrelated thoughts," Pagnoni said.