An Overview of the Science Behind Brain Shift Radio
by Jeff Strong
BSR co-founder and chief tech and music developer
Brain Shift Radio is all about the brain. The core of BSR is our ability to directly stimulate brain activity. This approach requires two separate but tethered neurological mechanisms: synchronization and stimulation.
I'll cover these in detail below but first I want to provide a basis and foundation for the use of musical rhythm to influence brain activity. The core components of the techniques used for the music on Brain Shift Radio have been used around the world for tens of thousands of years.
Here is an excerpt from article I wrote that was published in the Open Ear Journal ("Blending ancient techniques with modern research findings", 10/02):
From the shamans of Outer Mongolia to the Manbos of the Caribbean, rhythm has been used for thousands of years as a means to create and maintain health and well being. There is hardly a place on this planet where rhythm, usually in the form of drumming, hasn't embedded itself into the very fabric of society - often becoming an essential part of creating and maintaining spiritual, mental, and physical health. In spite of the many differences among ancient societies, very few differences emerged among their therapeutic rhythm techniques.
In fact, only three core approaches developed: Community drumming, shamanic drumming, and rhythm-healing. Community drumming focuses on shared rhythm-making and the effects of playing an instrument with other people, whereas shamanic drumming and rhythm-healing employ very specialized rhythmic techniques designed to have a prescribed effect on the listener.
Rhythm-healing is an ancient approach that uses complex rhythms that are designed to influence the internal rhythms of the individual. Rhythm-healing is based upon the theory that specialized rhythmic drumming patterns can influence the internal rhythmic patterns of the individual and correct those which are thought to be out of synch and causing illness.
Specific rhythms, when administered correctly, may be used to affect the emotions, pain levels, nervous system function, and organ function. This technique has been used for thousands of years to treat a variety of conditions. Rhythm-healing has been practiced by indigenous societies in West Africa, Central America, North America, South America, and the Caribbean. Rhythm-healing relies on a key part of our biology: External rhythms can influence the body's own internal rhythms...
... Like Rhythm-healing, Shamanic drumming is an ancient, almost universally used technique. This technique is part of the larger shamanic healing tradition. Shamanism is considered the world's oldest organized healing system - estimated to be between 20,000 and 30,000 years old - and can be found in nearly every pocket of the earth. In his book, 'The Way of the Shaman', Michael Harner writes that shamanic techniques are "strikingly similar the world over, even for peoples whose cultures are quite different in other respects, and who have been separated by oceans and continents for tens of thousands of years." The core aspect of shamanic drumming is the use of a repetitive rhythm to affect the listener's state of consciousness.
Synchronization is when brain wave activity, as measured by EEG, matches that of the pulse of the rhythm in the music. This is a phenomenon called brainwave entrainment. Brainwave entrainment techniques have been around for many thousands of years (of course, these ancient cultures had no idea that they were doing this - they only knew it felt good). These ancient approaches used percussion instruments, like we do with Brain Shift Radio; but there are some other brainwave entrainment approaches being used today, including binaural beats, beat frequencies, isochronic beats, and tone bursts, to name a few.
All of these rely on this concept of entrainment. Entrainment, by definition, is the synchronization of similar rhythmic cycles. Entrainment is present in all fields of science, but from a biological perspective it can have a major impact on us. The most obvious and pervasive form of entrainment is our synchronization to the day/night cycle.
We are all entrained to the movement of the sun and moon. We are generally not aware of our reliance on this entrainment to function, but we run smack into it whenever we travel long distances in a short period of time, Flying from the San Francisco to Tokyo, for example, throws us far enough off our cycle that we need time to adjust to our new daytime. We call this jet lag and it can take a couple of days to re-entrain.
In the case of brainwave entrainment and Brain Shift Radio the brainwaves are one rhythm and the percussion produces the other. This is the synchronization aspect of BSR.
The synchronization happens as a result of the underlying pulse of the rhythm tracks. These are described in beats per second (BPS). Brain Shift Radio utilizes rhythms ranging from about 2 to 13 BPS. These pulses are all within the range of human consciousness, which refer to BPS as Hz (hertz. 1 Hz = 1 BPS). Here is a breakdown of the 4 basic levels of human consciousness and how they relate to BPS:
Delta: .1-3 Hz. This is our deep sleep state (stages 3 and 4).
Theta: 4-7 Hz. This is a meditative and REM sleep state where our focus tends to be more internally directed.
Alpha: 8-12 Hz. This is a relaxed, yet alert state and is also present during REM sleep.
Beta: 13-30 Hz. This is our normal wakeful state.
The process of synchronizing the brain through auditory stimulus is often referred to as auditory driving. Research on auditory driving can be divided into three basic categories: drumming, tone bursts, and beat frequencies.
Drumming: Early research into the ability of repetitive drumming to direct consciousness showed an entrainment mechanism (Neher, 1962, Jilek, 1975), but left many questions as to why this was happening. A study conducted in 1993 answered many of the questions still remaining about the ability of repetitive drumming to drive brain wave states (Maxfield, 1994). In this study, Maxfield showed a direct correlation between the tempo of the rhythm played and the brain wave activity in the listener's brain. Maxfield also showed that the rhythm need not be repetitive in order to facilitate this entrainment response. This is important because typical auditory driving mechanisms have been less effective at an alpha tempo than theta due to the habituation that often happens with the repetitive rhythmic stimulus that has been presented in alpha. To prevent habituation, variations in the accents and tones are key to the stimulation effects inherent in REI.
By being able to vary the rhythms in BSR tracks, habituation becomes much less of a barrier to initiating auditory driving. A variable rhythm is a crucial component when attempting to drive the brain into an alpha level of activity, simply because a repetitive pulse in the alpha range causes habituation before entrainment can commence.
Beat Frequencies/binaural beats: Beat frequencies and binaural beats are pulsations that the brain perceives when two dissimilar tones are heard bilaterally. Beat frequencies were the results of research conducted by several people and first published by Gerald Oster in 1973. Considerable study has been done with beat frequencies and binaural beats (Owens & Atwater 1995; Hiew 1995; Hink, et al, 1980; Foster 1990; Oster, 1973; Sadigh, 1990).
Tone Bursts: Over the last twenty years researchers have been experimenting with computer-generated, repetitive rhythms called tone bursts (Kalluri S, Delgutte B., 2003; Joris, et al, 1994). Tone bursts use the same basic approach as ancient shamanic drum rhythm except the white noise tone used theoretically eliminated any interference caused by the frequencies produced by the drum. This interference was suggested by Jilek but was observed by Maxfield not to be an issue.
Another reason tone bursts have become many researcher's method of choice is that beat frequencies have proven to have limitations, especially at alpha, and using a computer generated white noise rhythm employs a higher technology than using a drum. This makes it more attractive to researchers.
You'll find BPS listed in the descriptions of many of the rhythm tracks. BSR contains rhythm tracks that have BPS between about .5 to 13. You can see which brain state we're entraining to based on these bps numbers as they relate to the four basic levels of human consciousness. One of the keys to the effects of the BSR rhythms tracks is the variable nature of the tempos within each track. With most tracks you'll see several different tempos included.
This lets us drive your brain in ways that a single pulse can't and allows for the subtleties necessary for your brain to respond. Rating the tracks helps us understand your brain type and we use this data to give to better and better mixes.
The stimulation aspect of Brain Shift Radio is produced by the accents and tonal variations in the rhythms. These variations engage the brain via their unpredictability (novelty). The rhythm tracks in BSR contain unusual patterns. Because these patterns are not familiar to you, your brain becomes engaged (active) trying to figure them out. The more unusual the patterns the harder your brain works to try to decipher them (referred to as complexity). In most cases the patterns also change frequently. This keeps your brain guessing abut what is going to happen next, thus keeping it engaged and active (referred to as unpredictability).
Research on novel auditory stimulus suggests that listener's brain activity increases with the introduction of a novel stimulus as part of the Central Nervous System (CNS) orientation response (Knight, 1996). It has also been shown that novel rhythmic stumuli can increase brain activity even for people with severe neurological disorders (Parsons, 1996, Rossignol, S.; Melvill Jones, G. 1976, Scartelli, 1987).
The Brain Shift Radio rhythm tracks vary in complexity and predictability. Multiple drum tracks are generally consistent rhythmically, (like regular music) making them less complex. They also remain the same for long periods of time (again, like regular music), which makes them predictable. Both of these factors make them less stimulating than many other rhythm tracks.
Single drum tracks (or even multiple drum tracks with solos), on the other hand, use rhythmic patterns that are more difficult to understand and change patterns frequently. This means the brain works harder to understand the rhythms . Familiarity causes a decrease in neuron firing response (Rutishauser et al, 2006) and makes the rhythms less effective; keeping the rhythms complex and changing keeps the brain active.
Single drums tracks, though sometimes uncomfortable to listen to, provide the most activation in the brain. The best way to make the rhythms comfortable is to either mix them into the background behind the ambient track or to turn the overall volume down. At BSR we talk a lot about keeping the volume low and rating tracks so that we can understand how much complexity (stimulation) you can handle.
Your other option to keep from becoming uncomfortable by the music on BSR is to choose less intense rhythms. Each rhythm track is rated for a specific intensity based on the complexity of the patterns and the frequency with which they change. You can learn more about choosing track and intensity levels here: http://brainshiftradio.com/resources/rhythm-and-ambient.html