Types of brain waves and their functions
Did You Know?
When we fall asleep, a large number of neurons in our brain tend to fire in synchrony, resulting in the production of high-amplitude delta waves in the brain.
Our brain emits waves, which are nothing but electrical signals generated when neurons are 'firing' messages to one another. The brain has approximately 80 to 100 billion neurons―specialized cells that communicate with each other by transmitting electrical impulses through neuronal connections.

The quicker the neurons fire at the same time, higher will be the frequency of waves. The more the neurons fire synchronously, the higher will be the amplitude of the wave. Depending upon the frequency and the type of activity associated with it, following are the different types of brain waves.
Beta Waves
Beta wave
These high frequency waves (12 to 40 Hz) are produced in the brain when we are fully involved in some kind of mental activity. We are in a state of complete alertness and totally focused on the task at hand. A strongly engaged mind is the hallmark of people who spend their time in a beta state. Having an active conversation, playing sports, giving a presentation or attending a job interview requires you to be in a state of increased alertness, which has been associated with the production of beta waves. When there is a dominance of beta wave activity, the mind is sharp, and the person is able to think fast and come up with new ideas quickly. The stimulation of beta waves increases our concentration and problem-solving ability, which in turn helps improve our peak performance.
Alpha Waves
Alpha wave
Alpha waves that travel in the range of 8 to 12 Hz, correspond to relaxation, sense of calm and well-being. Generation of alpha wave pattern is an indication of semiconscious state. The person is neither sleepy nor is attentive about his/her surrounding environment. For instance, just after finishing an assigned task, we tend to be in a relaxed state of mind, which is nothing but the alpha state. It is a 'resting state' in which we take a break from our work schedule and just refresh ourselves. So, during this pleasant 'alpha' break, you may prefer to watch TV, take a 5-10 minute walk in the backyard or simply sit and think over new ideas to resolve an existing issue. Alpha state is relaxing but at the same time, this phase or state may prompt us to come up with innovative solutions to some challenging problems.
Theta Waves
Theta wave
Theta waves are slower than alpha waves and their frequency varies from 4 to 8 Hz. We often enter this relaxed state of consciousness while performing a repetitive activity such as having a shower, brushing teeth, watering plants, or driving on the same route everyday to reach office. All these activities are highly monotonous, which make us feel calm, and we tend to mentally drift to a slower state of theta brain wave activity.

Theta waves are also generated while daydreaming, fantasizing, imagining, and intuitive thinking. Some of the best creative ideas may pop up in your mind during the theta state. When in theta state, the mind disengages itself from reality and focuses more on imaginative thinking.
Delta Waves
Delta wave
Delta waves have the lowest frequency (less than 4 Hz) among others and signify unconscious state of being. No wonder, a person in a deep sleep shows delta wave activity in the brain. These high amplitude slow frequency waves are emitted when we are in deep sleep. The production of delta wave pattern that is marked by total loss of awareness, allows the body and the brain to heal. No wonder, delta waves that help revitalize the brain are also referred to as healing frequencies. This delta wave pattern has also been detected in deeper meditative states.
There is one more band of brain waves, referred to as gamma waves. They correspond to moments of ecstasy and high energy states in which focus and concentration are at their highest levels. They are considered to be the fastest wave types with frequency ranging from 40 to 100 Hz. However, the fact is our brain seldom shows gamma activity, and usually, it works in the frequency range associated with beta, alpha, theta, and delta waves.
A point to note here is that, although beta waves are generated often during the day, it does not mean that the other 3 brain waves are absent. When one type of brain wave is dominant, the rest are feeble but continue to be detected. So, the brain produces all 4 waves at all times; only the strength of the signal will vary depending upon the type of activity we are engaged in.