Brainwave Coherence During the Transcendental Meditation technique

What is Brainwave Coherence?

Brain researchers have found that during practice of the Transcendental Meditation technique, the brain becomes more coherent and integrated, and that this heightened efficiency of brain functioning grows over time through twice-daily practice — even outside of meditation — improving mental performance.

Everyone’s brain emits faint electrical impulses, and these impulses can be measured and recorded by EEG (electroencephalographic) monitoring devices. In an EEG measurement, sensors (electrodes) are placed on the scalp to detect and record patterns of electrical activity. The data measured by the EEG can be used for clinical and research purposes.
Typical EEG Tracings from non-meditating subject. Each line represents output from an electrode sensor placed on the scalp.
An EEG measurement identifies wavelengths—or frequencies—of brainwaves. During ordinary waking consciousness, EEG patterns are generally scattered, disorderly, and rapidly changing. 

By contrast, as the mind settles into the practice of the Transcendental Meditation technique, brainwaves tend to become rhythmic and orderly—to fall into “phase”—and move synchronously over large areas in the frontal regions of the brain (as shown below), extending eventually toward the posterior regions as well. This is called EEG coherence.*
EEG tracings recorded during practice of the TM technique. The lines are moving up and down together — brain waves are no longer scattered but "in phase," indicating that neurons are firing in harmony within the same frequency of alpha2. 
Higher coherence is associated with more integrated and effective thinking and behavior, including greater intelligence, creativity, learning ability, emotional stability, ethical and moral reasoning, self-confidence, and reduced anxiety.

Everything good about the brain depends on its coherent, orderly functioning. Recent studies in neuroscience have found that world-class athletes have higher EEG coherence than controls, and higher-performing CEO's display greater coherence than other executives.

Researchers have long known that most experiences, whether sensory or cognitive, enliven only small, specific portions of the brain. Studies on brain patterns during TM practice indicate that the technique enlivens coherence over a wide area—creating more efficient coordination of brain activity and stimulating the growth of what scientists propose to be “total brain” functioning.

EEG studies showing brainwave coherence during practice of the TM technique along with synchronized alpha power in the frontal cortex have established the EEG signature for “restful alertness” or "pure consciousness," the inner experience commonly reported by people practicing the Transcendental Meditation technique.

Scientific References: Cognitive Processing 11:1 (2010); Consciousness and Cognition, 8, 302-318, 1999; International Journal of Neuroscience 14: 147–151, 1981; Science 167 (1970); Scientific American 226 (1972); American Journal of Physiology 221 (1971); Electroencephalography and Clinical Neurophysiology 35 (1973).

Read more on The Huffington Post: "Keeping Your Prefrontal Cortex Online: Neuroplasticity, Stress and Meditation"

*TECHNICAL: EEG coherence is a measure of correlation or synchrony of the EEG waves recorded at two points on the scalp. Mathematically, it is the absolute value of the cross-correlation function in the frequency domain of two electrical signals. Coherence reflects the number and strength of connections between two brain areas. Higher coherence indicates that these two points of the brain are working more closely together.

Normally applied to scalp EEG sensors that detect cortical neuron activity in the area below the sensor, the electrical waves are computer analyzed in a very precise manner to determine how similar the two waves are to each other over time. Specifically, the brainwave pattern from two points of the scalp are analyzed first for a given frequency band, say, alpha—between 8 and 12 cycles per second. These two converted signals are then examined over about a 1-2 second period to get an average value of the similarity in the upward and downward movement of each of the two waves. Thus, the researcher obtains an accurate measure of the constancy of the phase relationship of the two wave patterns over a given time period. This constancy is closely correlated with fundamental modes of brain information transfer.