The Synchronised Brain

What happens to the brain in meditation? This has been the question many scientists have been posing ever since interest in this field began, midway through this century. The brain is of central interest, acting us a. focusing point between both mind and body research. Scientists hope that by learning about the effects of meditation on the nervous system, they will be able to follow its effects into the body and gain a better understanding of its potential use for relaxation of mental tension, thereby opening the way to higher understanding.

In 1955, Das and Gastaut recorded fast frequencies (intense beta waves) synchronously produced by the brain in kriya yoga practice indicating intense one-pointed concentration and associated with subjective feelings, of ecstasy and bliss.*1

In 1961, Anand et al. pointed out the prominence of alpha waves plus the absence of reaction to external stimuli in practitioners of deep meditation. These studies of introversion, pratyahara, showed that it is possible to go into a state of consciousness where awareness is maintained even though it appears as though we are asleep.*2

In 1970, Wallace remarked that the appearance of theta waves occurred in the frontal area of the brain during japa meditation, which seems to indicate relaxation of the intellectual and worrying aspects of the brain.*3

Following on from this, J.P. Banquet has researched the alterations of EEG in meditation with an aim to distinguish this state from other states of consciousness (waking, dreaming and sleeping). The following is a summary of his experiment and the results of his research.*4

The experiment

Twelve long term meditators and twelve control subjects who had never meditated were used. They were measured by EEG (electrical activity of the brain), EMG (electrical activity of the muscles), and respiratory rate trials.

After resting for five minutes with their eyes open and then five minutes with their eyes closed, the meditators used their mantra for thirty minutes while the controls sat with their eyes closed. During this time they were asked to come out of the meditation or relaxation approximately three times and also to concentrate on a thought or image with their eyes closed for approximately five minutes. A pushbutton with a five signal code allowed the subjects "to indicate the psychological events occurring during meditation or relaxation: body sensation, involuntary movement, visual imagery, deep meditation and transcendence (the deepest point of meditation)".

After this they were interviewed as to the quality and events of their meditation or relaxation.

The results

The control group of twelve people was found to be naturally divided into three groups of four subjects:

Group A did not relax. They showed dominant beta waves and muscle activity.

Group B relaxed successfully. They alternated between alpha dominant and beta dominant activity. Their muscles relaxed during alpha activity.

Group C dozed or fell asleep. Two subjects showed alpha waves with mainly low voltage delta and some slow theta waves. These are characteristic of dozing or drowsiness. The other two showed high voltage delta waves without alpha, which are characteristic of sleep.

The meditators showed the following changes in the different parameters:

  • a) Resting stage - alpha activity (frequency ten cycles/second, amplitude fifty micro volts) in all subjects. This is typical of rest and relaxation in all 'normal' people.
  • b) Meditation - in the first phase of meditation, alpha increased in amplitude up to seventy micro volts. In ten subjects the frequency slowed by one or two cycles/second, spreading from the back of the head to the frontal lobes, which can be interpreted as indicating slowing of intellectual activity. This implies that early on in meditation, anxiety and worry are reduced, the centres for these functions in front of the brain being tranquillised.
    A second phase emerged in which alpha waves slowed and a dominant theta pattern developed (high voltage up to 100 micro volts, and frequency between five and seven cycles/second). At first this phase lasted only one or two seconds, but gradually extended from ten seconds to several minutes. This, Banquet reports, was unlike the pattern seen in drowsiness. These signals emerged firstly in the frontal channels and spread to the back (occipital region). Theta Waves, usually seen only in drowsiness and dreaming, have been correlated in meditation with subjective feelings of spontaneity, creativity and awareness of different planes of inner experience.
    A third phase emerged in four meditators which they indicated on their pushbutton device as indicating deep meditation or even transcendence. This was a fast frequency pattern, mainly beta waves (around twenty to forty cycles/second) which reached surprisingly high voltages (thirty to sixty micro volts). This confirms the findings of Das and Gastaut during kriya yoga meditation. In Banquet's work it was mainly found in the frontal brain, but was occasionally seen synchronously spread throughout the whole brain. Beta waves are usually found in extroversion but in this experiment the waves were seen in deep meditation which seems to imply that the meditators had broken through into a form of concentrated awareness of the inner dimension. This is evidenced by the fact that the fast frequencies occurred on a persistent background of slower activity and relaxation.
    The three phases were progressive but not individualised, as two major frequencies could appear simultaneously. Several cycles occurred in the thirty minute meditation period.
  • c) Coming out of meditation - alpha returned.
  • d) Concentration - produced alpha waves and brief periods of beta.
  • e) Open eyes- some advanced meditators maintained alpha which is an apparently rare phenomena, and is correlated with relaxation. The author suspected that this is unique to meditation as it had not been reported in biofeedback or other relaxation methods.


In meditation the brain tended to synchronise:

  1. Alpha waves spread from the back of the head to the front.
  2. Theta and beta waves spread from front to back.
  3. Beta waves occurred first in the left hemisphere and then both sides equalised.
  4. In the phase between slow and fast frequencies, a transient asymmetry between right and left hemispheres sometimes occurred.
  5. "There were periods of uniformity of frequency, amplitude and wave form in all channels", the researcher reported.

These patterns of waves indicating changes in the rain are totally different from those of the non-meditators who do not show ordering and 'synchronisation' of waves, but rather mixtures and alteration "I alpha, low delta and discontinuous theta frequencies. Non-meditators tended to doze and sleep. Meditators did not sleep as they could perform voluntary movements at any stage without altering brainwaves and could answer questions 'readily and accurately'.

Banquet suggests that his findings could be interpreted as meaning that even though the subject is aware of internal and external stimuli during meditation, he does not react. At the same time there is the simultaneous persistence of an alert state of consciousness allowing the subject to memorise and answer questions.

"We must deduce, therefore, that the EEG changes of meditation are independent of the interaction between the subject and the outer world but produced by the specific mental activity of the practice. The Initiation of a loop between the cortex, thalamo-cortical co-ordinating system, and the sub cortical rhythm generator (Andersen and Andersson 1968 *5) could account for the different alterations."*6

Yogic interpretation

Meditation seems to help us relax by reducing the chaotic patterns of brainwaves that most people produce and which are linked to anxiety, neurosis and other forms of suffering, as well as the reduction of vital body energy. By inducing relaxation, meditation allows more energy to be used for constructive mental activity. It quietens the thinking process (increased frontal lobe alpha waves) and according to authorities it concentrates all the functions of rain under the control of one central mechanism.

This may occur during pratyahara so as to produce synchronised brainwaves in both hemispheres, either as alpha, theta or beta. Subjectively, the meditator feels more relaxed, stronger, more energised and better able to function in the outside world when he emerges from the meditative state, as there can be a carry-over of alpha or theta into the normal conscious state. In the long term, the meditator benefits greatly from such an ordered and synchronised reorganisation of neural tissue and its link to the mind.


*1. N.N. Das & Gastaut, "Variations de l'activite electrique du cerveau, du coeur et des muscles squelettiques au cours de la meditation et de I'extase yogique", 'Electroenceph. clin. Neurophysiol, suppl.' 6: 211-219, 1957.

*2. B.K. Anand, G.S. Chhina, B. Singh, "Some Aspects of Electroencephalographic Studies in Yogis", 'Electroenceph. clin. Neurophysiol.', 13: 452-6, 1961.

*3. R.K. Wallace, "Physiological Effects of Transcendental Meditation", 'Science', 167: 1751-4, 1970.

*4. J.P. Banquet, "Spectral Analysis of the EEG in Meditation", 'Electroenceph. Clin. Neurophysiol., 35: 143-151, 1973.

*5. P. Andersen & S.A. Andersson, 'Physiological Basis of the Alpha Rhythm', Appleton-Century-Crofts, New York, 1968, p. 235.

*6. J.P. Banquet, 'op. cit.' p. 150.