The brain emits electromagnetic impulses with everything it does; from thoughts, to memories, to words, the brain is vibrating at different frequencies depending on our consciousness. Named after Greek letters, Alpha, Beta, Delta, Theta and Gamma, brainwaves are described below:

Alpha: This is a baseline, slow, light sleep, or calm brain function state, often found in between sleep and dreams, in which one can have creative ideas or visions. Also found when conversing.

Beta: Normal waking consciousness, known as the arousal state because the mind is active.

Delta: Deep sleep, non REM, with no awareness of the physical body. If awake in the Delta state, one can have visionary experiences.

Gamma: The highest frequency brainstate, emitted when intensely focused.

Theta: The brain state during REM sleep when we’re dreaming. Also possible during trance, leading to visionary experiences.

It is possible to entrain brain waves using sound. When two inconsistent sounds are combined and heard by each ear at inaudible levels, the brain emits a pulse of electromagnetic energy, which can be measured in one of the brainstate ranges. Often bass lines, particularly in electronic music, are an easy and quick way to entrain brain waves, moving from Beta, or normal consciousness, to the higher intensity brainwaves, inducing a flow state.

In meditation, holistic practitioners and scientists have found the use of binaural beats to affect the brain’s state. Using headphones, the brain hears two different sounds at once, coming from different ears, and produces a third sound in resonance to the sound’s frequency. This effect can be measured by a medical instrument called an EEG.
The simplest way to adjust your brain state is to close your eyes. Switching from attentive beta, to relaxed alpha; and if one is able to bring to mind calming images, the brain may transition to an even higher state such as theta.

The brain may be entrained not only by sound but also by light, called photic driving. Caused by rhythmic light emissions, the brain convulses to match the light, accompanied by a surge of brain chemicals that emit signals.

While humans entrain to music and light through the vibration of brain chemicals, we also entrain to each other. Feelings of harmony and discord can be measured in the frequencies we emit, either matching and providing happy brain chemicals, or in discord, vibrating negatively to each other.