Mar. 31, 2010 — Forget about
crystals and candles, and about sitting and breathing in awkward ways.
Meditation research explores how the brain works when we refrain from
concentration, rumination and intentional thinking. Electrical brain
waves suggest that mental activity during meditation is wakeful and
relaxed.
"Given the popularity and effectiveness of meditation as a means of
alleviating stress and maintaining good health, there is a pressing need
for a rigorous investigation of how it affects brain function," says
Professor Jim Lagopoulos of Sydney University, Australia. Lagopoulos is
the principal investigator of a joint study between his university and
researchers from the Norwegian University of Science and Technology
(NTNU) on changes in electrical brain activity during nondirective
meditation.
Constant brain waves
Whether we are mentally active, resting or asleep, the brain always
has some level of electrical activity. The study monitored the frequency
and location of electrical brain waves through the use of EEG
(electroencephalography). EEG electrodes were placed in standard
locations of the scalp using a custom-made hat
Participants were experienced practitioners of Acem Meditation, a
nondirective method developed in Norway. They were asked to rest, eyes
closed, for 20 minutes, and to meditate for another 20 minutes, in
random order. The abundance and location of slow to fast electrical
brain waves (delta, theta, alpha, beta) provide a good indication of
brain activity.
Relaxed attention with theta
During meditation, theta waves were most abundant in the frontal and middle parts of the brain.
"These types of waves likely originate from a relaxed attention that
monitors our inner experiences. Here lies a significant difference
between meditation and relaxing without any specific technique,"
emphasizes Lagopoulos.
"Previous studies have shown that theta waves indicate deep
relaxation and occur more frequently in highly experienced meditation
practitioners. The source is probably frontal parts of the brain, which
are associated with monitoring of other mental processes."
"When we measure mental calm, these regions signal to lower parts of
the brain, inducing the physical relaxation response that occurs during
meditation."
Silent experiences with alpha
Alpha waves were more abundant in the posterior parts of the brain
during meditation than during simple relaxation. They are characteristic
of wakeful rest.
"This wave type has been used as a universal sign of relaxation
during meditation and other types of rest," comments Professor Øyvind
Ellingsen from NTNU. "The amount of alpha waves increases when the brain
relaxes from intentional, goal-oriented tasks.This is a sign of deep
relaxation, -- but it does not mean that the mind is void."
Neuroimaging studies by Malia F. Mason and co-workers at Dartmouth
College NH suggest that the normal resting state of the brain is a
silent current of thoughts, images and memories that is not induced by
sensory input or intentional reasoning, but emerges spontaneously "from
within."
"Spontaneous wandering of the mind is something you become more aware
of and familiar with when you meditate," continues Ellingsen, who is an
experienced practitioner. "This default activity of the brain is often
underestimated. It probably represents a kind of mental processing that
connects various experiences and emotional residues, puts them into
perspective and lays them to rest."
Different from sleep
Delta waves are characteristic of sleep. There was little delta
during the relaxing and meditative tasks, confirming that nondirective
meditation is different from sleep.
Beta waves occur when the brain is working on goal-oriented tasks,
such as planning a date or reflecting actively over a particular issue.
EEG showed few beta waves during meditation and resting.
"These findings indicate that you step away from problem solving both when relaxing and during meditation," says Ellingsen.
Nondirective versus concentration
Several studies indicate better relaxation and stress management by
meditation techniques where you refrain from trying to control the
content of the mind.
"These methods are often described as nondirective, because
practitioners do not actively pursue a particular experience or state of
mind. They cultivate the ability to tolerate the spontaneous wandering
of the mind without getting too much involved. Instead of concentrating
on getting away from stressful thought and emotions, you simple let them
pass in an effortless way."
Take home message
Nondirective meditation yields more marked changes in electrical
brain wave activity associated with wakeful, relaxed attention, than
just resting without any specific mental technique.
Source: http://www.sciencedaily.com/releases/2010/03/100319210631.htm
