What is brainwave entrainment?

Brainwave entrainment, also known as 'brainwave synchronization' is a practice that depends upon a 'frequency following' response from your brain, following a dominant external stimulus. Usually, the external stimulus is a specialized software, but it can also be a pulse of sound or light.
When the brain receives an external stimulus, through ears, eyes or any other senses, it emits a response which is called a 'cortical evoked response'. These electrical responses travel throughout the brain and they can be measured using sensitive devices attached to the scalp.
When the rhythmic stimulus presented to the brain is, for example, a drum beat, the rhythm is reproduced in the brain in the form of a 'cortical evoked respose'. If the rhythm becomes fast and consistent enough, it can start to resemble the natural internal rhythms of the brain, called 'brainwaves'. When this happens, the brain starts responding by synchronizing its own electric cycles to the same rhythm as the drum beat. This is usually called a 'Frequency Following Response' or FFR.

Another 10 interesting facts about our brain

The weight of the human brain is about 1.3-1.4 kg.

Your brain uses 20% of the total oxygen in your body.

The next time you get a fever, keep in mind that thehighest human body temperature ever recorded was 46.5 C –and the man survived.

It is thought that a yawn works to send more oxygen to the brain, therefore working to cool it down and wake it up.

Your brain is 60% white matter and 40% gray matter.

Every time you recall a memory or have a new thought, you are creating a new connection in your brain.

Memories triggered by scent have a stronger emotional connection, therefore appear more intense than other memory triggers.

Memory is formed by associations, so if you want help remembering things, create associations for yourself.

A newborn baby’s brain grows about three times its size in the first year.

Excessive stress has shown to alter brain cells, brain structure and brain function.

Brainwaves described

It is very important to understand how your brain works and how it contributes to your state of mind. Most of us are used to focus on our emotions trying to become happier or a more spiritual being. What most of you don’t know is that your brain waves and your subcionscious mind play a big part in this pursuit of happiness.
Let’s take a look at your brain wave frequencies and how they affect the state of mind. Each frequency is measured in cycles per second (Hz) and has its own set of characteristics. Each of these waves represent a specific level of brain activity and a unique state of consciousness.

Let’s begin with Beta. Its range is 14-40Hz and is the wave of your wide awake state.
Beta brain waves are associated with normal waking consciousness and an increased state of alert, logic and critical reasoning.
Beta brain waves are essential for your effective functioning throughout the day, but they can also translate into a stressful, restless and anxious mind. 
Imagine Beta as that annoying little inner critic that gets louder and louder. Once it gets lounder, it means that your brain waves are high into above mentioned range and that stress is just around the corner or it has already arrived.
The majority of adults operate at Beta, this is why stress is the most common problem these days.

About brainwaves

Our brain is made of billions of cells called neurons. To communicate with each other, neurons use electricity. The combination of millions of neurons sending signals at once produces an enormous amount of electrical activity in the brain, which can be detected using sensitive medical equipment, measuring levels of electricity over areas of the scalp.
The combination of electrical activity of the brain is commonly called a 'Brainwave pattern', because of its cyclic, wave-like nature.
Our mind regulated its activities by means of electric waves which are registered in the brain, emiting tiny electrochemical impulses of varied frequencies, which can be registered by an electroencephalogram (EEG).
With the discovery of brain waves, came the discovery that electrical activity in the brain will change depending on what the person is doing. For instance, the brainwaves of a sleeping person are vastly different than the ones of someone wide awake. Over the years, more sensitive equipment has brought us closer to figuring out exactly what brainwaves represent and with that, what they mean about a person's health and state of mind.
The known brainwaves and their associated mental states are:
- Beta emited when we are consciously alert, or we feel agitated, tense, afraid.
- Alpha when we are in a state of physical and mental relaxation, but aware of what is happening around us.
- Theta which is a state of somnolence with reduced consciusness.
- Delta when there is unconsciousness, deep sleep or catalepsy.