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
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 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:
In meditation the brain tended to synchronise:
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
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.