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Several years later, Dr. Gregg Jacobs, a professor of psychiatry at Harvard Medical School who worked with Benson, recorded EEGs of one group of subjects taught to meditate and another given books on tape with which to chill out. Over the next few months, the meditators produced far more theta waves than the book listeners, essentially deactivating the frontal areas of the brain that receive and process sensory information. They also managed to lower activity in the parietal lobe, a section of the brain located near the top of the head that orients you in space and time. By shutting down the parietal lobe, you can lose your sense of boundaries and feel more "at one" with the universe, which probably feels a lot less boring than it sounds when you try to tell your friends about it.
Studies of the meditating brain got much more sophisticated after brain imaging was discovered. Or maybe not. In 1997 University of Pennsylvania neurologist Andrew Newberg hooked up a group of Buddhist meditators to IVs containing a radioactive dye that he hoped would track blood flow in the brain, lighting up the parts that were the most active. But the only way for Newberg to freeze-frame the exact moment when they reached their meditative peak was to sit in the next room, tie a string around his finger and snake the other end under the door and leave it next to the meditators. When they reached meditative Nirvana, they pulled the string, and Newberg released the dye into the subjects' arms. His results showed that the brain doesn't shut off when it meditates but rather blocks information from coming into the parietal lobe. Meanwhile, Benson took a group of highly focused Sikhs who could meditate while an fMRI machine clanked away, and he measured the blood flow in their brains. Overall blood flow was down, but in certain areas, including the limbic system (which generates emotions and memories and regulates heart rate, respiratory rate and metabolism), it was up.
At the University of Wisconsin at Madison, Richard Davidson has used brain imaging to show that meditation shifts activity in the prefrontal cortex (right behind our foreheads) from the right hemisphere to the left. Davidson's research suggests that by meditating regularly, the brain is reoriented from a stressful fight-or-flight mode to one of acceptance, a shift that increases contentment. People who have a negative disposition tend to be right-prefrontal oriented; left-prefrontals have more enthusiasms, more interests, relax more and tend to be happier, though perhaps with less real estate.
Studies on meditation moved into the modern era in March 2000, when the Dalai Lama met with Western-trained psychologists and neuroscientists in Dharamsala, India, and urged the Mind and Life Institute to organize studies of highly accomplished meditation masters using the most advanced imaging technology, the results of which will be discussed in September at a conference at M.I.T. (which will also plan the next stages of research). Not only did these studies allow for a more detailed understanding of how the brain works during meditation, but they also provided a lot of cool shots of monks wearing electrodes.