Kundalini.Tantra.by.Satyananda.Saraswati

Measuring the waves in the brain
As we start to practise meditation we initially experience its calming, relaxing and
stabilizing effects. Prolonged practice, and especially the more vigorous forms of
meditative practice take us far beyond these preliminary changes which many modern
researchers have been stressing as the main aim and effect of meditation. After some
time, actual psychophysiological changes take place and amongst these there is a change
in the mode of functioning of our nervous system.
In order to measure these changes Bentov used a modified ballistocardiograph, a
machine which measures small body motions accompanying the motion of blood through
the circulatory system. (2) "A subject sits on a chair between two metal plates, one above
the head and one under the seat, 5 to 10 centimeters from the body. The two plates of the
capacitor are part of a tuned circuit. The movement of the subject will modulate the field
between the two plates. The signal is processed and fed into a single channel recorder
which registers both the motion of the chest due to respiration and the movement of the
body reacting to the motion of the blood in the heart-aorta system." (3)
Bentov states that the spinal cord can be thought of as a spring which, during
meditation, reacts to the movement of blood into the heart and circulatory system. The
heart pumps blood into the large blood vessel called the aorta. The aorta is curved on top
(at the level of the bottom of the neck) and bifurcated at the bottom (in the lower
abdomen). Every time blood enters the aorta it moves upward towards the head and this
gives a minute upward push to the upper part of the body. The blood then moves
downward to strike the bifurcation of the aorta, gently pushing the body downward. This
movement is called micromotion and the movement recorded on the ballistocardiograph
is only in the order of 0.003 to 0.009 millimeters, a very minute amount.
This gentle upward and downward movement has the tendency to oscillate the whole
body, spine and skull up and down. The natural rhythm of this oscillation is 7
cycles/second (7 Hertz, Hz). Of course in the normal situation we do not feel such minute
micromotion, however, in the deep stillness of profound meditation even the slightest and
most subtle movement of the body or thought creates ripples within the nervous system
which, to our introverted consciousness, become magnified and disturb inward progress.
Yogis have always stressed that the most important preliminary ingredient for
meditation is to develop a straight and strong spinal cord through asana and to gradually
develop stillness of the body, nervous system and mind through pranayama.Through
Bentov's model we can now see that this is because immobility of body, breath and mind
sets the stage for the production of rhythmic waves within the spine, skull and
cerebrospinal fluid (CSF).
When subjects are in a deep meditative state, Bentov's machine measures an almost
pure, regular, S-shaped sine wave of large amplitude and moving at approximately 7
cycles/second. This is opposed to an irregular wave in the baseline resting state before
and after meditation. Something happens in meditation which does not normally occur in