EEG Studies on Yogis and Zen Meditations:
Dada krpamayananda
EEG Studies on Yogis
and Zen Meditations:
Yogis practicing Raja-Yoga claim that during the state
of samadhi they are oblivious to the internal and
external stimuli, and they enjoy a calm ecstasy during that state. A study was undertaken to record the electrical
activity of their brain during this state by means of a regular and useful test
known as electroencephalography EEG.
Physiological and experimental studies have demonstrated that the basis of
conscious state of brain, among other things, is due to activation of
"reticular system" in the brain-stem in response to internal and
external stimuli. These stimuli
bring about various changes during sleeping and wakeful states of the organism
and these can be studied by EEG.
The study was carried out
on four subjects during the state of concentration and meditation. Effects of external stimuli, like a loud gong,
strong light, thermal simulation, and vibrations were studied. The results were compiled and analyzed. It was observed that two Yogis could keep their
hands immersed in extremely cold water for about 50 minutes (raised pain
threshold). During
state of meditation, all of them showed persistent "alpha activity"
in their EEG with increased amplitude wave pattern, both during 'eyes closed'
and 'eyes open' recording. It was
observed that these alpha activities could not be blocked by various sensory
stimuli during meditation. It
was also observed that those, who had well-marked "alpha activity" in
their resting EEG showed greater aptitude and zeal for maintaining the practice
of Yoga. Similar observations and
results were obtained when EEGs were recorded in persons adept in Zen Meditative
technique.
In the 1970's J.P. Banquet studied twelve TM practitioners and twelve controls who were about to learn TM. He found that subjects practicing TM had distinctive EEG changes, including slow high-amplitude alpha activity extending to anterior channels, theta activity different from sleep, rhythmic amplitude-modulated beta waves present over the whole scalp, and synchronization of anterior and posterior channels.
Studies of Zen
Buddhist Monks
In a study that attracted much attention among meditation
and biofeedback researchers during the 1960s, Akira Kasamatsu
and Tomio Hirai, physicians at the University of Tokyo,
studied the EEG changes exhibited during meditation by Zen teachers and their
disciples (forty-eight in all) from Soto and Rinzai centers
in Japan. For experimental control, they studied the EEGs of
twenty-two subjects with no experience at meditation.
They made EEG recordings; recorded their subjects' pulse rates, respiration,
and galvanic skin response; and tested their responses to sensory stimuli
during meditation. The recordings on
the Zen monks were made during a weeklong retreat, or sesshin,
at a Zendo, except for a few tests at the
experimenters' laboratory. The Zen
teachers and their most experienced students exhibited a typical progression of
brain-wave activity during meditation, which Kasamatsu
and Hirai divided into four stages:
* Stage 1: Appearance of
alpha waves in spite of opened eyes.
* Stage 2: Increase in
amplitude of persistent alpha waves.
* Stage 3: Decrease in alpha
frequency.
* Stage 4: Appearance of
rhythmical theta trains (Kasamatsu and Hirai, 1966).
Not all four stages were
evident in every Zen practitioner, nor in any of the controls, but a strong
correlation existed between the number of stages a given student exhibited and
that student's length of time in Zen training.
This correlation was supported by a Zen teacher's evaluation of each student's
proficiency. The teacher ranked the
students in three levels, without seeing their EEG records, and his rankings
correlated well with Kasamatsu and Hirai's assessment
of their EEGs.
The Kasamatsu-Hirai
study also revealed significant differences between four Zen masters and four
control subjects in their response to repetitive click stimuli. Like the Zen masters, the controls exhibited a
blocking of alpha when a click sound first occurred, but they gradually became
habituated to such stimuli so that their brain-wave activity no longer
responded when a click was made. The
Zen masters, however, did not become habituated, but continued to exhibit
blocking as long as the stimuli continued.
This finding indicates that Zen practice promotes a serene, alert awareness
that is consistently responsive to both external and internal stimuli (Kasamatsu et al.,
1957; Hirai, 1960; and Kasamatsu and Hirai, 1963).
The Medline database contains
reports that have been published in recognized research magazines, more than
27,000 reports on relaxation, yoga and meditation published over the last
twenty years. It becomes apparent
some of the researchers regard meditation as an unalterable quantity. Therefore they cannot understand why there is a
discrepancy in their research. The
fact is that the results largely depend on which meditation technique is used.
In some meditations you
learn to withdraw the senses; in others you are more present in your senses. There are meditations where you learn to make your
mind one-pointed, and meditations without a focal point, which are based on the
ability to experience the totality in and around oneself.
It should also be added that some methods give only a light relaxed state,
while others produce very clear changes in your general state. Certain Tantric
meditations, for example Inner Silence, are constructed as a developing
sequence containing a whole array of the mentioned methods - it spans the
spectrum from outer awareness to deep inner rest in oneself.
IBVA brain data during
meditation here soon. (last edited 05.09.05)
|
||||||||||||||
|
|
||||||||||||||
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.362 / Virus Database: 267.13.7/182 - Release Date: 24/11/2005