Brain Waves

What does one experience while meditating or doing Yoga???


A tiny electrical activity is always present throughout the body and is a by product of the activity within every living cell. As long as one is alive, his/her body cell will be involved in some kind of activity. Though as an organic whole, we often become oblivious of various kind of activities happening inside our body, they are always there inside and can be measured using specialized equipments.

All these activities are being performed by trillions of living cells in your body. Individual biological cells survive by transferring electrically charged particles, called ions, across their cell membranes. This flow produces an electrical current that could be detected with sufficiently sensitive equipment. Measuring the electrical activity of the heart and brain is an established medical procedure, but detecting normal cellular electrical activity at a micro-level is still a major challenge. However, scientists are working on solving this problem.

Your brain is made up of billions of brain cells called neurons, which use tiny electric impulses to communicate with each other.

The combination of millions of neurons sending signals to each other produces an enormous amount of electrical activity in the brain, which can be detected using sensitive medical equipment. The combination of electrical activity of the brain is commonly called a Brainwave pattern, because of its cyclic, ‘wave-like’ nature. The electroencephalograph (EEG) was invented by Hans Berger in 1930.

The EEG recording, called an electroencephalogram displays the electrical activity as waves, which in the past was drawn onto paper like a seismograph, and is now digitized in most labs. This wave-like property of the electrical signals led to the term “brainwaves.”

Depending upon their frequencies, these brainwaves have been classified into 5 categories :

Human head and brain. Different kind of waveforms produced by brain activity shown on background. Digital illustration.

  • Gamma (30-70Hz),
  • Beta (13-30Hz),
  • Alpha (8-13Hz),
  • Theta (4-8Hz); and
  • Delta (1-4Hz).

Although any of these frequencies can occur at any electrode site of the brain, alpha waves are often recorded at posterior sites, theta waves at frontal sites, and gamma waves over sensory cortices.

Each of these wave patterns have been correlated through studies with various conscious phenomena such as sleep, attention, meditation, hypnosis, music, and relaxation etc. other areas.