The brain is an extremely complex organ which communicates via electrical impulses between neurons. An electroencephalogram (EEG) is a device which measures the frequency and amplitude of these electrical impulses (i.e. “brain waves”). Studies have shown that meditation practices can induce different EEG states in practitioners.
For instance, one review found that relaxation-based meditations induces a larger proportion of alpha wave (8-12 hz) and theta wave (4-8 hz) activity in the brain, which are characterized by rest.
In addition, yoga nidra practitioners have been shown to induce slow wave delta wave activity (0.5-4 hz) — that is, EEG activity exhibited during deep sleep stages, while paradoxically remaining conscious. Delta waves contain a “down state,” where neurons in the neocortex are silent and able to rest.
Finally, studies have shown that some advanced Buddhist meditators are able to self-induce high frequency gamma waves (25-42 hz) during practice. Gamma wave activity has been associated with heightened perceptual clarity and superior cognitive control of thought and emotional expression.
Why is this important?
As workaholic North Americans, our brains spend a lot of the day producing beta waves, that is characterized by states of heavy information processing. Too much beta wave activity is associated with anxiety, insomnia, anger, and paranoia– it is not surprising that many of us suffer from illnesses related with these states of mind. Thus, meditation breaks can be highly beneficial for controlling differing levels of brain wave frequencies protective of mental illness.
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