Hearing is one of the five human senses and allows us to discern in reality. The hearing center in the human brain continues to work even during sleep, constantly analyzing the sounds that reach us. Sound affects our state of consciousness and changes the frequency of brain waves.
Human brain activity levels
The human brain reaches certain states related to its activity (the so-called bioelectric activity). We call these states phases and we can measure them with an electroencephalograph (EEG) by expressing their values in hertz (Hz). The lowest activity of the brain is the epsilon phase with a frequency of up to 0.5 Hz. We know very little about this phase. In this state, heart rate and breathing are virtually imperceptible. Brain activity from 0.5 Hz to 4 Hz is called the delta phase. This phase is associated with deep sleep, the state of meditation (the so-called delta meditation), it is accompanied by increased creativity and sensory integration. Delta waves calm the mind and body, and their increased activity is associated with access to information in the unconscious mind. It has been proven that increasing the number of delta waves in many cases eliminates headaches. At the 4 Hz level, theta phase begins which extends to a frequency of 7.5 Hz. Theta waves are associated with deep relaxation, sleepiness, inner focus, meditation, creative thinking and free flow of ideas, but also with short-term and long-term memory. Most likely, it is in this phase that the learned content is absorbed and consolidated. Theta waves appear during meditation or a deep hypnotic trance (logical relationships disappear), as well as in moments of experiencing strong emotions related to fulfillment, satisfaction or pleasure. Frequencies from 7.5 Hz to 12 Hz are reserved for the alpha phase, which is the main rhythm of the mind in adults who are in a state of relaxation and so-called unconsciousness. Alpha waves also appear during REM sleep. The alpha phase is associated with a good mood, feeling calm, and it is perhaps the most desirable brain state. This state is very useful when practicing meditation (so-called “open focus”), in the process of releasing everyday stress and pain, but also in learning. From 12 Hz to 38 Hz, our brain is in the beta state, i.e. in a typical daily rhythm, which is manifested by the activity of thinking, attention and focus on the outside world. Beta waves appear during active involvement in various mental activities, for example, when solving analytical problems or making decisions, but also accompanies emotions of agitation, fear and tension. Above the beta state, in a wide frequency range starting at 39 Hz and ending at 90 Hz, we recognize the gamma phase in brain activity. This phase is characteristic of the occurrence of complex brain processes and improves the perception of individual senses. A large amount of gamma wave activity is associated with the development of self-awareness, intelligence and self-control, but also with emotions accompanying compassion and love. Gamma waves are considered to be the best natural anti-depressant. The highest activity of the brain is called the lambda phase. It occurs on the level from 91 Hz to 200 Hz. This state, although not yet thoroughly researched, is ascribed to higher levels of consciousness.
The cerebral hemispheres
When considering how the brain works, two hemispheres are worth mentioning: the left and the right. In most cases, the left hemisphere is responsible for logical, rational, mathematical, analytical thinking and for verbal processes. The right hemisphere, on the other hand, is characterized by holistic, intuitive, symbolic, imaginative, and image-based thinking. While studying the brain activity of people with above-average intelligence, it was discovered that their hemispheres are synchronized with each other, that these people use both hemispheres simultaneously. In addition, scientists also conducted research on a group of advanced yogis, zen monks and shamans who were trained in various types of meditation techniques. It turned out that their brains in the states of deep meditation showed exceptionally high synchronization of the left and right hemispheres, as well as a significant predominance of alpha (7.5 Hz – 12 Hz) and theta (4 Hz – 7.5 Hz) brain waves.
In 1839, the German physicist and meteorologist Heinrich Wilhelm Dove, conducting experiments in the field of meteorology, accidentally discovered the phenomenon of binaural beats. More advanced research on this subject was developed only in the second half of the 20th century, during the research related to the development of meditation techniques. In technical terms, the phenomenon of binaural beats relies on some specific ability of the human brain to register phase differences in the sound that is heard.
The binaural-beat effect is where the brain makes the impression of hearing one vibrating sound, despite the fact that two different (but similar) sounds are introduced into each ear. To experience binaural beats, use stereo headphones.
Since sound is a mechanical wave, its graph resembles a sine wave in which we can distinguish phase (top) and counter-phase (bottom). Overlapping waves of the same frequency can behave in two ways: strengthen or suppress each other. Two waves will be amplified (i.e. synchronized) when their phases and the counter-phases coincide with each other (top to top, bottom to bottom). On the other hand, we will talk about attenuation when the phase of one wave coincides with the counter-phase of the other wave (top to bottom and bottom to top). When we superimpose two slightly different sounds, the phase of one in successive cycles will move towards the antiphase of the other until it overlaps, and then it will move towards the phase, also until it overlaps. Put simply, this means that these sounds will amplify and fade out, alternating with the frequency of the difference between the opening sounds. This is how the binaural beat is produced. The easiest way to describe it is using an example. Imagine introducing a 400 Hz sound to the left ear and 409 Hz to the right ear. Theoretically, we would expect to hear two different sounds, but since the difference between them does not exceed 30 Hz, the brain surprises us and produces a kind of vibrato-effect third sound. The difference of 9 Hz between the left and right sounds means that in one second we will hear 9 times the sound of maximum intensity (two phases overlapping each other) and 9 times silence (not total). For a binaural beating effect to occur, two conditions must exist: the different sounds delivered to each ear must be lower than 1000 Hz, and the difference between them must be less than 30 Hz.
Jak wpłynąć dźwiękiem na pracę mózgu?
Scientists, including neurobiologists in particular, prove that music provides us not only with aesthetic impressions. It turns out that it is also a powerful tool that can be used to change the physiological states of the brain, and thus biochemical changes throughout the body. It has been proven beyond doubt that binaural beats synchronize the work of the cerebral hemispheres. In addition, it has been recorded that they also affect the change of brain waves, i.e. the level of brain activity, by stimulating and reducing the activity of the central nervous system. It turns out that the so-called functional currents of the cerebral cortex of a person exposed to binaural beats adapt to the frequency of the beats themselves. This means that with the help of binaural beats we can synchronize the work of the hemispheres of our brain, and we are also able to adjust its work to the desired state. Of course, such a process is a bit more complicated and involves more elements, but it must be admitted that we can influence the work of the brain with sound. To achieve the best results, comprehensive techniques have been developed that combine binaural beats, affirmations, meditation, visualizations, and special breathing techniques.
Imagine how amazing it is for us to achieve, for example, a state of deep relaxation. By achieving such a state, we will relax not only the body, but also the mind, leading the body towards homeostasis, which in turn will reduce tension, facilitate blood flow, provide oxygen and nutrients to cells, strengthen the immune system, improve the quality of sleep, and these are just some of them. among many benefits.
Where to get binaural beats from?
There are many sites on the Internet that offer comprehensive binaural-beat systems in combination with other techniques. YouTube will also be a great resource. However, the safest way will be to test ready-made applications available for smartphones (Brain Wave, Binaural Beats and a whole lot of others).
Article published in the magazine Harmonia. Your health, your responsibility in the March / April 2021 issue.