Meditation

It’s well established that stress interferes with cognitive processes like memory and concentration, but recent studies reveal that stress can also seriously impair judgment.  University of Washington researchers found that just one episode of severe stress induced by periodic electric tail shocks for 60 minutes in restrained rats, affected their normal ability to navigate a maze in order to receive a reward and this persisted the following day.  It was also found that if the rats were given a small dose of muscimol, a drug that temporarily inactivates the amygdala prior to being subjected to the same stress, they behaved as if nothing had happened, and this protective effect lasted for 24 to 48 hours.  The amygdala has numerous connections to other brain structures, including the hypothalamus, which stimulates the sympathetic nervous system during “fight or flight” situations, thalamic cells that increase reflex responses, cranial nerves responsible for facial expressions of fear, and other sites that produce dopamine and other neurotransmitters.

Stress has also been shown to affect crucial brain cells in humans, especially in developing brains, and a warping effect can be demonstrated on MRI scans. Prenatal or early childhood stress can lead to an inability to learn and remember as well as undesirable changes in behavior such as substance abuse, as well as psychiatric disorders.  In one study (that could not be performed in humans), in which immobilized mice subjected to loud rock music, MRIs showed a loss of fibers responsible for communication between brain cells.

Conversely, meditation can protect your brain, as assessed by cutting edge technologies like functional magnetic resonance imaging (fMRI), which measures the blood flow in different parts of the brain and shows how active they are.  Emory researchers had previously reported that longtime meditators don’t show the usual loss of gray matter in their brains as they age. Other studies have found that meditators have thicker tissues in the prefrontal cortex, the region that governs attention and control, suggesting a neuroprotective effect.

This experiment involved 12 seasoned meditators, including several monks, who practiced Zen meditation daily for at least 3 years and 12 controls who had never meditated.  They were asked to follow their breathing while looking at a screen on which actual words or meaningless combinations of letters that looked like words that were flashed at irregular intervals.  Participants had to decide whether they were seeing a real or fake word and signal by pressing a button before returning to focus on their breathing.  Zen (zazen) practitioners are taught to notice when the mind starts to wander and to quickly return to a meditative state by focusing on their breathing.  It is not surprising therefore that the meditators were able to recover from this distraction much more rapidly than controls and fMRIs confirmed this, as well as a greater volume of grey matter, especially in the putamen, a brain structure linked to attention.   Studies are now in progress to determine if meditation simply slows the loss of grey matter with aging, or causes the formation of new grey cells.

 

ZAFUS and ZABUTONS