Brain waves are oscillating electrical voltages in the brain, measuring just a few millionths of a volt. At the root of all our thoughts, emotions, and behaviors are the communication between neurons within our brains. Brainwaves are produced by synchronized electrical pulses from masses of neurons communicating with each other.
Brainwaves are detected using sensors placed on the scalp. They are divided into bandwidths to describe their functions but are the best thought of as a continuous spectrum of consciousness, from slow, loud, and functional — to fast, subtle, and complex.
It is a handy analogy to think of brainwaves as musical notes — the low-frequency waves are like a deeply penetrating drum beat, while the higher frequency brainwaves are more like a subtle high pitched flute. Like a symphony, the higher and lower frequencies link and cohere with each other through harmonics.
Our brainwaves change according to what we’re doing and feeling. When slower brainwaves are dominant, we can feel tired, slow, sluggish, or dreamy. The higher frequencies are dominant when we feel wired or hyper-alert.
The descriptions that follow are only broad descriptions — in practice, things are far more complex, and brainwaves reflect different aspects of different locations in the brain.
Brainwave speed is measured in Hertz (cycles per second), and they are divided into bands delineating slow, moderate, and fast waves.
Infra-Low brainwaves (also known as Slow Cortical Potentials) are thought to be the basic cortical rhythms that underlie our higher brain functions. Very little is known about infra-low brainwaves. Their slow nature makes them difficult to detect and accurately measure, so few studies have been done. They appear to play a major role in brain timing and network function.
Delta (δ) Waves (0.5 TO 4HZ) — Sleep
Delta brainwaves are slow, loud brainwaves (low frequency and deeply penetrating, like a drumbeat). They are generated in deepest meditation and dreamless sleep. Delta waves suspend external awareness and are the source of empathy. Healing and regeneration are stimulated in this state, and that is why deep restorative sleep is so essential to the healing process.
Theta brainwaves occur most often in sleep but are also dominant in deep meditation. Theta is our gateway to learning, memory, and intuition. In theta, our senses are withdrawn from the external world and focused on signals originating from within. Twilight states that we normally only experience fleetingly as we wake or drift off to sleep. In theta, we dream; vivid imagery, intuition, and information beyond our normal conscious awareness. It’s where we hold our ‘stuff,’ our fears, troubled history, and nightmares.
Alpha (α) Waves(8 TO 12 HZ) — Very relaxed, Passive Attention
Alpha brainwaves are dominant during quietly flowing thoughts and in some meditative states. Alpha is ‘the power of now,’ being here, in the present. Alpha is the resting state of the brain. Alpha waves aid overall mental coordination, calmness, alertness, mind/body integration, and learning.
Beta brainwaves dominate our normal waking state of consciousness when attention is directed towards cognitive tasks and the outside world. Beta is a ‘fast’ activity, present when alert, attentive, engaged in problem-solving, judgment, decision making, or focused mental activity.
Beta brainwaves are further divided into three bands; Lo-Beta (Beta1, 12–15Hz) can be thought of as a ‘fast idle’ or musing. Beta (Beta2, 15–22Hz) is the high engagement or actively figuring something out. Hi-Beta (Beta3, 22–38Hz) is a highly complex thought, integrating new experiences, high anxiety, or excitement. Continual high-frequency processing is not a very efficient way to run the brain, as it takes a tremendous amount of energy.
Gamma (γ) Waves(35 TO 42 HZ) — Concentration
Gamma brainwaves are the fastest brain waves (high frequency, like a flute) and relate to the simultaneous processing of information from different brain areas. Gamma brainwaves pass information rapidly and quietly. The most subtle of the brainwave frequencies, the mind has to be quiet to access gamma.
Gamma was dismissed as ‘spare brain noise’ until researchers discovered it was highly active in states of universal love, altruism, and the ‘higher virtues.’ Gamma is also above the frequency of neuronal firing, so how it is generated remains a mystery. It is speculated that gamma rhythms modulate perception and consciousness and that a greater presence of gamma relates to expanded consciousness and spiritual emergence.
New Trial to Test Brain Wave Stimulation as Alzheimer’s Preventative
With a new $1.8 million grant from the Part the Cloud-Gates Partnership Grant Program of the Alzheimer’s Association, researchers at Massachusetts Institute of Technology and Massachusetts General Hospital are launching a new clinical trial to test whether stimulating a key frequency of brain waves with light and sound can prevent the advance of Alzheimer’s disease pathology even before volunteers experience symptoms such as memory impairment.
“Because Alzheimer’s disease leads to neurodegeneration and cognitive decline, the best time for intervention may be before those symptoms even begin,” said Dr. Li-Huei Tsai, Picower Professor of Neuroscience and director of The Picower Institute for Learning and Memory at MIT. “We are hopeful that our safe, non-invasive approach of sensory stimulation of 40Hz gamma brain rhythms can have a preventative benefit for patients. We are very grateful to Part the Cloud-Gates Partnership Grant Program for their support in funding rigorous research to test this exciting possibility.”
In extensive testing in Tsai’s lab with multiple mouse models of Alzheimer’s, the light and sound stimulation technique, called Gamma ENtrainment Using Sensory Stimuli (GENUS), improved cognition and memory, prevented neurodegeneration, and reduced amyloid and tau protein buildups. The research showed that increasing 40Hz brain rhythm power and synchrony stimulated the brain’s immune cells and blood vessels to clear out the toxic proteins. Early results from human testing at MIT show that GENUS is well tolerated and increases 40Hz power and synchrony, just like in the mice.
The new study, conducted in collaboration with neurologist Dr. Keith Johnson at MGH, will enroll 50 volunteers aged 55 or older who show signs of amyloid protein plaque buildup in PET scans but remain cognitively normal. Experimental volunteers will receive an hour of GENUS light and sound stimulation in their homes daily for a year. At regular checkups, the team will monitor GENUS's effect on amyloid buildup via PET scans as well as other biomarkers such as tau and for changes in cognition, sleep, structural and functional MRI, and other indicators of brain function and health.
The trial will be double-blinded, randomized, and controlled, meaning that some volunteers will be exposed to non-GENUS light and sound during the trial to provide a non-treatment comparison group. To ensure that bias does not influence the results, neither the volunteers nor the experimenters will know which group's volunteers are.