What Are Binaural Beats?
Binaural beats – also known as Auditory Beat Stimulation (ABS) – are created by the brain when two separate frequencies of sound are played in each ear at the same time using earphones.
How Are Binaural Beats Created?
Our brain will perceive the volume of these two sounds, by creating an illusionary beat or fixed rate pulse, in order to move or swing the sound back and forth into a regular rhythm. Depending on what binaural beat frequencies we are listening to, will influence the brain wave state.
Now that we understand that our brains are an autorhythmic muscle, the real question is, how are binaural beats created?
“Monaural and binaural beats are generated when sine waves of neighboring frequencies and with stable amplitudes are presented to either both ears simultaneously (monaural beats) or to each ear separately (binaural beats). Monaural beats are physical beats, which are objectively heard when the combination of two sine waves atUS National Library of Medicine
neighboringfrequencies (e.g., 400 and 440 Hz) are summated and presented to each ear at the same time resulting in an amplitude modulated (AM) signal. The beat corresponds to the difference between the two frequencies (in this case 40 Hz). Binaural beats are generated when the sine waves within a close range are presented to each ear separately. For example, when the 400 Hz tone is presented to the left ear and the 440 Hz tone to the right, a beat of 40 Hz is perceived, which appears subjectively to be located “inside” the head. This is the binaural beat percept. The binaural beat percept was first reported by H. W. Dove in 1839 and outlined in detail by Oster over five decades ago. Oster reported that the binaural beats were detected only when the carrier frequency was below 1000 Hz, a finding that confirmed an earlier study by Licklider and colleagues. This indicates that beat carrier frequencies have to be sufficiently low enough to be temporally encoded by the cortex.”
National Institutes of Health
What Are Brain Waves And How Are They Measured?
Neurons – also known as neurones, nerve cells and nerve fibres – are electrical cells in the nervous system that function to process and transmit information. These neurons will create a different frequency that reflects what we are doing and feeling due to their electrical voltage.
Brain Waves & Neurofeedback:
Most of us are unaware of the various brainwaves we experience throughout the day, nevertheless, with the help of Neurofeedback – a type of biofeedback, also referred to as Neurotherapy that uses real-time displays of brain activity through electroencephalography (EEG) – allows us to learn and teach the self-regulation of brain function.
The most commonly known and researched brain waves are listed below with results of each, from Neurofeedback:
Infra-low (<.5 Hz) Slow Cortical Potentials: Basic, cortical rhythms that underlie our higher brain functions.
“These brainwaves reach the physiological core of who we are, giving the brain a “second chance” to self-regulate, especially when brains present extremely high arousal conditions: ADHD, bipolar, the autism spectrum, attachment issues and post-traumatic stress.”Neuro Clinic
Delta Waves (.5 Hz To 3 Hz): Generated conscious in deep meditation and dreamless sleep.
“The lowest frequencies are delta. These are less than 4 Hz and occur in deep sleep and in some abnormal processes. It is the dominant rhythm in infants up to one year of age and it is present in stages 3 and 4 of sleep. It tends to be the highest in amplitude and the slowest waves. We increase Delta waves in order to decrease our awareness of the physical world. We also access information in our unconscious mind through Delta. Peak performers decrease Delta waves when high focus and peak performance are required. However, most individuals diagnosed with Attention Deficit Disorder, naturally increase rather than decrease Delta activity when trying to focus. The inappropriate Delta response often severely restricts the ability to focus and maintain attention. It is as if the brain is locked into a perpetual drowsy state.”Neurohealth Associates
Theta Waves (3 Hz To 8 Hz): Deep relaxation, meditation and imagination.
“Cortical theta is observed frequently in young children, but in older children and adults, it tends to appear during meditative, drowsy, or sleeping states (but not during the deepest stages of sleep). When we are awake, excess theta levels can result in feeling scattered or day-dreamy and is commonly reported in ADHD. Too much theta in the left hemisphere is thought to result in lack of organisation, whereas too much theta on the right results in impulsivity. Theta in people with attention disorders is often seen more towards the front of the brain.
Frontal Midline Theta: Sinusoidal and high in amplitude (1-10 second bursts), generally occurs in response to events (ie. an ERP). This midline theta is associated with opening the sensory gate to the hippocampus for intermediate storage of episodic information. The frequency of frontal midline theta varies from 5-7.5 Hz, with an average of 6Hz. This rhythm is associated with working memory, episodic encoding and retrieval. It also appears during hypnosis and deep meditation. Frontal midline theta is thought to originate from the anterior cingulate. It mainly appears when one is performing a task requiring focused concentration, and its amplitude increases with the task load. It is mainly concentrated around Fz. When anxious and restless, the signal is reduced or even eliminated. When anxiety is medicated, the signal is restored. This suggests that the anterior cingulate cortex is involved in regulating the emotional state from restless anxiety to focused relaxation.
Hippocampal Theta: Has been found in the posterior cingulate, entorhinal cortex, hypothalamus and amygdala. Often more tonic and diffuse, and elicits and coordinates memory.”Neurofeedback Alliance
Alpha Waves (8 Hz To 12 Hz): associated with relaxation and contemplation, however, depending on the frequency, they can also be great for maintain focus, study and creativity.
“Alpha waves are present at different stages of the wake-sleep cycle. The most widely researched is during the relaxed mental state, where
the subjectis at rest with eyes closed,but is not tired or asleep.
This alpha activity is
centeredin the occipital lobe ,and is presumed to originate there, although there has been recent speculation that it instead has a thalamic origin. This wave begins appearing at around four months and is initially a frequency of 4 waves per second. The mature alpha wave, at 10 waves per second, is firmly established by age 3.
The second occurrence of alpha wave activity is during REM sleep. As opposed to the awake form of alpha activity, this form is located in a frontal-central location in the brain. The purpose of alpha activity during REM sleep has yet to be fully understood. Currently, there are arguments that alpha patterns are a normal part of REM sleep, and for the notion that it indicates a semi-arousal period. It has been suggested that this alpha activity is inversely related to REM sleep pressure.
It has long been believed that alpha waves indicate a wakeful period during sleep. This has been attributed to studies where subjects report non-refreshing sleep and have EEG records reporting high levels of alpha intrusion into sleep. This occurrence is known as alpha wave intrusion. However, it is possible that these explanations may be misleading, as they only focus on alpha waves being generated from the occipital lobe.”Wikipedia
Beta Waves (12 Hz To 38 Hz): Normal, conscious waking experience; thinking, focussing, tension, alertness, excitement.
“Because beta waves have a wide range in frequency (from approximately 12 hertz to 38 hertz), individuals may experience different states of mind during different frequencies. For example, an individual who has a lower beta wave frequency may experience alertness, clear thinking, and/or creative thinking. The lower frequencies within beta waves are close to alpha waves (approximately 8 hertz to 13.9 hertz). Remember, individuals whose brain activity reflects alpha waves are in states of deep relaxation. Therefore, the closer an individual’s brain activity is at a frequency of around 13.9 hertz, the more alert and clear his or her thinking will be.
On the other end of the spectrum, an individual who has a higher beta wave frequency may experience restlessness, anxiety, stress, and/or panic. The higher the frequency, the more your brain is working to rapidly send signals to other parts of the body. It takes a lot of energy from the brain to maintain these higher brain wave frequencies because the brain is doing more than it would in a relaxed state. As a result, it can negatively affect an individual’s health, as seen in the potential symptoms previously listed. Furthermore, a brain that is consistently in a
high frequencystate creates an imbalance in the system as the brain may be overexerting itself. This, too, can create issues in an individual’s physical and/or emotional health.
The more stress the brain is under, or the longer it maintains a high frequency, the more it releases a stress hormone called cortisol. Recent studies on cortisol have revealed that chronic stress and high cortisol levels can have multiple negative effects on the brain.”San Diego Center For Neurofeedback
Gamma Waves (38 Hz To 42 Hz): The fastest and yet most subtle of the brain waves, relating to the simultaneous processing of information from different areas within the brain. There are also some theories, yet to be proven, that Gamma waves, create the unity of conscious perception – a matter of global neural networks.
“Subjects: There were 12 adults in 2 groups (N = 12): 6 practitioners of Transcendental Meditation™ and six controls.
Measures: The measures were self-assessed inner experiences and measurements of clarified gamma output at the prefrontal cortical region.
Results: (1) Self-assessed descriptions were comparable for both groups; (2) the associations of 16 supplied descriptors with the initial neurofeedback experience were comparable for both groups and showed highest scores for “happy” (p < 0.0001) and “loving” (p < 0.0001), and lowest scores for “stressed” (p < 0.0001) and “disappointed” (p < 0.0001); (3) baseline measures were comparable for both groups; (4) both groups were able to increase gamma brainwaves using neurofeedback (p < 0.01); and (5) meditators produced greater increases over controls (p = 0.02).
Conclusions: The inner experience associated with increased clarified gamma amplitude from the prefrontal cortex apparently involves positive emotions of happiness and love, along with reduced stress. Meditators achieved greater increases in the gamma band from the prefrontal cortical region over controls during an initial neurofeedback session.”The Journal of Alternative and Complementary Science
Have you tried Binaural Beats for yourself? It can be difficult finding good quality beats, however, there are vast amounts available for free, on YouTube that you can check out.
For more information on the discovery of Binaural Beats, I recommend reading the Binaural Blog that delves deep into the history of binaural stimulations.
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