What are Brain Waves

The Brain-Wave Investigation

The brain is powered by electricity. Each of its billions of individual cells “fires,” or electrically discharges, at a specific frequency. The electrical activity of the brain can be monitored by placing sensors or electrodes against the scalp, which register the minute electrical signals happening inside the brain, much the way a seismograph can detect tremors taking place inside the earth. The device that registers these signals is called an electroencephalograph, or EEG. The EEG measures not the firings of individual brain cells, but rather the cooperative or collective electrical patterns of networks or communities of millions of cells firing together—fluctuations of energy sweepings across the networks of the brain. These collective energy pulsations are called brain waves.

Since the first EEG was devised in the 1920s, scientists have found that the brain has a tendency to produce brain waves of four distinct varieties, which they have called beta, alpha, theta, and delta.

Beta Waves The most rapid brain waves, beta waves, range in frequency from about 14 cycles per second (called 14 Hertz, abbreviated Hz) to more than 100 Hz. When we are in a normal waking state, eyes open, focusing on the world outside ourselves or dealing with concrete, specific problems, beta waves (particularly those between 14 and 40 Hz) are the most dominant and powerful waves in the brain. Beta waves are associated with alertness, arousal, concentration, cognition, and—at excessive levels—anxiety.

Alpha Waves As we close our eyes and become more relaxed, passive, or unfocused, brain-wave activity slows down, and we produce bursts of alpha waves, which range in frequency from about 8 to 13 Hz. If we become quite relaxed and mentally unfocused, alpha waves become dominant throughout the brain, producing a calm and pleasant sensation called the alpha state. The alpha state seems to be the brain’s “neutral” or idling state, and people who are healthy and not under stress tend to produce a lot of alpha activity. Lack of significant alpha activity can be a sign of anxiety, stress, brain damage, or illness.

Theta Waves as calmness and relaxation deepen into drowsiness, the brain shifts to slower, more powerfully rhythmic theta waves, with a frequency range of about 4 to 8 Hz. Theta has been called the twilight state, between waking and sleep. It’s often accompanied by unexpected, dreamlike mental images. Often these images are accompanied by vivid memories, particularly childhood memories. Theta offers access to unconscious material, reveries, free association, sudden insight, creative ideas. It’s mysterious, elusive state, and for a long time experimenters had difficulty studying it because it is hard to maintain for any period of time. Most people tend to fall asleep as soon as they begin generating large amounts of theta.

Delta Waves As well fall asleep the dominant brain waves become delta, which are even slower than theta, in the frequency range below 4 Hz. When most of us are in the delta state we’re either asleep or otherwise unconscious. However, there is growing evidence that individuals may maintain consciousness while in a dominant delta state. This seems to be associated with certain deep trancelike or “non-physical” states. It is while we’re in the delta state that our brains are triggered to release large quantities of healing growth hormone.

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