Brain Activity and Meditation - Brainwaves
Brain Waves and States of the Mind
Your brain has a unique set of brain waves. In neuroscience, there are five distinct brain wave frequencies, namely Beta, Alpha, Theta, Delta and the lesser known Gamma. Learning mind control at the deeper states of consciousness opens you up to the world of your subconscious mind where you can create your reality at will and with exact precision.
Each frequency, measured in cycles per second (Hz), has its own set of characteristics representing a specific level of brain activity and hence a unique state of consciousness.
Beta (14-40Hz): Beta brain waves are associated with normal waking consciousness and a heightened state of alertness, logic and critical reasoning. As you go about your daily activities you are at Beta. Although important for effectively functioning in everyday life, higher Beta levels translate into stress, anxiety and restlessness.
With the majority of adults primarily operating at Beta during their waking hours it is little wonder that stress is today's most common health problem. The voice of Beta is the little nagging chatterbox of your inner critic, which becomes louder and more relentless the higher you go in the range.
Alpha (7.5-14Hz): Alpha brain waves are present in deep relaxation with the eyes usually closed and while day-dreaming. The relaxed detached awareness achieved during light meditation is characteristic of Alpha and is optimal for programming your mind for success. Alpha heightens your imagination, visualization, memory, learning and concentration.
It lies at the base of your conscious awareness and is the gateway to your subconscious mind. The renowned Silva Method by Jose Silva is premised on the power of Alpha. The voice of Alpha is your intuition, which becomes clearer and more profound the closer you get to 7.5Hz.
Theta (4-7.5Hz): Theta brain waves are present during deep meditation and light sleep, including the REM dream state. Theta is the realm of your subconscious mind. It is also known as the twilight state as it is normally only momentarily experienced as you drift off to sleep (from Alpha) and arise from deep sleep (from Delta).
A sense of deep spiritual connection and oneness with the Universe can be experienced at Theta. Vivid visualizations, great inspiration, profound creativity, exceptional insight as well as your mind's most deep-seated programs are all at Theta. The voice of Theta is silence.
Delta (0.5-4Hz): The Delta frequency is the slowest and is present in deep, dreamless sleep and in very deep, transcendental meditation where awareness is completely detached.
Delta is the realm of your unconscious mind. It is the gateway to the Universal mind and the collective unconscious whereby information received is otherwise unavailable at the conscious level. Delta is associated with deep healing and regeneration, underlining the importance of deep sleep to the healing process.
The Alpha-Theta border, from 7 to 8Hz, is the optimal range for visualization, mind programming and using the creative power of your mind. It is the mental state at which you consciously create your reality. At this frequency of mind control you are conscious of your surroundings but your body is in deep relaxation. To learn how to access this level of mind at will you must first learn how to relax.
Gamma (above 40Hz): The most recently discovered range is Gamma which is the fastest in frequency at above 40Hz (some researchers do not distinguish Beta from Gamma waves). Although little is known about this state of mind, initial research shows Gamma waves are associated with bursts of insight and high-level information processing.
In a nutshell, there are five major brain wave ranges: Beta (14-40Hz) is present in normal waking consciousness and stress; the Alpha brain wave (7.5-14Hz) in deep relaxation; Theta (4-7.5Hz) in meditation and light sleep; and the slowest, Delta (0.5-4Hz) in deep dreamless sleep and transcendental meditation. The less recognised Gamma is fastest (above 40Hz) and associated with sudden insight. The optimal level for visualization is the Alpha-Theta Border at 7-8Hz. It is the gateway to your subconscious mind.
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Meditation and its effect on brain activity and the central nervous system became a focus of collaborative research in neuroscience, psychology and neurobiology during the latter half of the 20th century. Research on meditation sought to define and characterize various practices. Meditation’s effect on the brain can be broken up into two categories: state changes and trait changes, respectively alterations in brain activities during the act of meditating and changes that are the outcome of long-term practice.
Highlighted region shows the anterior cingulate cortex, a region of the brain shown to be activated during meditation.
Mindfulness meditation is frequently studied, a Buddhist meditation approach found in Zen and Vipassana. Jon Kabat-Zinn describes mindfulness meditation as a complete, unbiased attention to the current moment.
Changes in brain state
Electroencephalography
Electroencephalography (EEG) has been used in many studies as a primary method for evaluating the meditating brain. Electroencephalography uses electrical leads placed all over the scalp to measure the collective electrical activity of the cerebral cortex. Specifically, EEG measures the electric fields of large groups of neurons. EEG has the benefit of excellent temporal resolution and is able to measure aggregate activity of portions or the entire cortex down to the millisecond scale. Unlike other imaging based methods, EEG does not have good spatial resolution and is more appropriately used to evaluate the running spontaneous activity of the cortex. This spontaneous activity is classified into four main classifications based on the frequency of the activity, ranging from low frequency delta waves (< 4 Hz) commonly found during sleep to beta waves (13–30 Hz) associated with an awake and alert brain. In between these two extremes are theta waves (4–8 Hz) and alpha waves (8–12 Hz).
Many studies on mindfulness meditation, assessed in a review by Cahn and Polich in 2006, have linked lower frequency alpha waves, as well as theta waves, to meditation. Much older studies report more specific findings, such as decreased alpha blocking and increased frontal lobe specific theta activity. Alpha blocking is a phenomenon where the active brain, normally presenting beta wave activity, cannot as easily switch to alpha wave activity often involved in memory recall. These findings would suggest that in a meditative state a person is more relaxed but maintains a sharp awareness. Two large, recent comprehensive review works, however, point to poor control and statistical analyses in these early studies and comment that it can only be said with confidence that increased alpha and theta wave activity exists.
Neuroimaging
Functional magnetic resonance imaging (fMRI) is another highly utilized methodology for studying state changes in meditating brains. fMRI detects subtle increases in blood flow to areas of the brain with higher metabolic activity. Thus these areas of increased metabolic activity indicate which regions of the brain are currently being used to process whatever stimuli presented. Counter to EEG, the advantage of fMRI is its spatial resolution, with the ability to produce detailed spatial maps of brain activity. It suffers, however, in temporal resolution and cannot measure progressive activity, like the EEG, with much detail.Topographical findings
As a relatively new technology, fMRI has only recently been used to assess brain state changes during meditation. Recent studies have shown heightened activity in the anterior cingulate cortex, frontal cortex, and prefrontal cortex, specifically in the dorsal medial prefrontal area during Vipassana meditation. Similarly, the cingulate cortex and frontal cortex areas were shown to have increased activity during Zen meditation. Both studies comment on the possibility that these findings could indicate some state of heightened voluntary control over attention during mindfulness meditation. Review works by Cahn and Chiesa state that these results indicate consistency in meditation’s effect on these regions of the brain, citing a multitude of other studies spanning other meditative disciplines, but mention the need for further investigation with better controls.
Study on meditation and emotion
The review by Cahn also notes findings describing a heightened emotional state of meditators. A more complex study, conducted in 2008 by Lutz et al., focused on emotional response during meditation. This investigation involved the creation of a “compassion meditation” state by novice and experienced meditators and testing the meditators response to emotionally charged sounds. fMRI results indicated heightened activity in the cingulate cortex but also in the amygdala, temporo-parietal junction, and right posterior superior temporal sulcus in response to the emotional sounds. The authors of this study believe this indicates greater sensitivity to emotional expression and positive emotion due to the neural circuitry activated.
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Changes in brain due to the prolonged practice
Electroencephalography
Similar to research into state changes in brain function, older studies make more specific claims about trait changes in meditators versus non-meditators. Changes to the alpha wave were indicated to be a trait, as well as state, phenomena. Studies have reported an increase in the specific frequencies expressed in the alpha range, increased alpha band power, and an overall slowing (reduction in frequency) in EEG activity in experienced meditators versus less experienced meditators while meditating.The alpha blocking phenomena, observed as a state change in brain function, was investigated as a possible trait change as well. One study that examined a variety of meditation techniques tried to show that alpha blocking was affected by the long term practice of meditation by testing response to auditory stimuli. Review works, however, comment on inconsistent findings as well as a lack of repeated results in this, and other studies. They further remark that, similar to observations in brain state changes, only general assertions can be made about brain trait changes: some change in the electroencephalographic profile exists but with some inconsistency. It is also important to note that these trait changes were observed during meditation, and although it does indicate that a practitioner’s electroencephalographic profile is modified by the practice of meditation, these EEG studies have not yet shown changes in non-meditating brains, even of experienced meditators.
Neuroimaging
Brain trait changes have also been observed in neuroimaging studies, most often employing fMRI. In a meta-analysis of 21 neuroimaging studies, eight brain regions were found to be consistently altered, including areas key to meta-awareness (frontopolar cortex/Brodmann area 10), exteroceptive and interoceptive body awareness (sensory cortex and insular cortex), memory consolidation and reconsolidation (hippocampus), self and emotion regulation (anterior cingulate cortex and orbitofrontal cortex), and intra- and interhemispheric communication (superior longitudinal fasciculus; corpus callosum) These changes were distinguished by density increases in grey matter regions and white matter pathways in the brains of individuals who meditate in comparison to individuals who do not. Of all areas with reported findings, a greater number of structural changes were found in the left hemisphere.
Red region of the brain shows the hippocampus which had been shown to have heightened activity during meditation by experienced meditators.
There is also evidence to suggest meditation plays a protective role against the natural reduction in grey matter volume associated with aging. One study found evidence that Zen meditators experienced a slower age related decline rate for cerebral gray matter volume in the putamen which plays a role in learning, cognitive flexibility and attentional processing This could suggest a better attentiveness in aging meditators versus non-meditators.
Long-term meditation practitioners have also shown to have a higher tolerance for pain. This effect has been correlated to altered function and structure in somatosensory cortices and an increased ability to decouple regions in the brain associated with the cognitive appraisal of pain (anterior cingulate cortex and dorsolateral prefrontal cortex).
The brain state changes found in meditators are almost exclusively found in higher-order executive and association cortices. This supports the notion that meditation increases self-regulation and attentiveness. Recent studies have also investigated how these changes may alter the functionality and connectivity of the default mode network, which is a hypothesized network of brain regions that are active when an individual is engaged in internal tasks such as daydreaming.
Validity of findings
In the meta-analysis performed by Fox et al., several sources of bias were indicated which bring into question the validity of meditation studies which use neuroimaging. Fox et al. suggests a publication bias may be leading to the over-reporting of significant results. Despite this, however, Fox et al. found "consistent differences in prefrontal cortex and body awareness regions" in "areas key to meta-awareness..., exteroceptive and interoceptive body awareness..., memory consolidation and reconsolidation..., self and emotion regulation..., and intra- and interhemispheric communication..." and that changes were significant with "moderate" global median effect size and "consistent and medium-sized brain structure differences."
More research will be needed before any firm conclusions can be made.
Positive portrayal
Besides scientific literature, some authors have written of the promising research on meditation in books targeted for general audiences.
EEG technology has been used for meditation research
One such book, Buddha’s Brain by Rick Hanson, PhD shares the current scientific research and investigations into meditation. Hanson, a neuroscientist and researcher, explains to readers the scientific studies in plain language and discuss the impact of the results. Hanson’s main argument is that positive emotions, like love can be strengthened through meditation in a neuroplastic manner, citing dozens of scientific studies to support this claim. Hanson’s viewpoint is representative of a larger popular movement to study and embrace Eastern phenomena including meditation in the Western world.
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Function of the various brainwaves
Ned Herrmann is an educator who has developed models of brain activity and integrated them into teaching and management training.
Before founding the Ned Herrmann Group in 1980, he headed management education at General Electric, where he developed many of his ideas. Here is his explanation.
It is well known that the brain is an electrochemical organ; researchers have speculated that a fully functioning brain can generate as much as 10 watts of electrical power.
Other more conservative investigators calculate that if all 10 billion interconnected nerve cells discharged at one time that a single electrode placed on the human scalp would record something like five millionths to 50 millionths of a volt. If you had enough scalps hooked up you might be able to light a flashlight bulb.
Even though this electrical power is very limited, it does occur in very specific ways that are characteristic of the human brain. Electrical activity emanating from the brain is displayed in the form of brainwaves. There are four categories of these brainwaves, ranging from the most activity to the least activity. When the brain is aroused and actively engaged in mental activities, it generates beta waves.
These beta waves are of relatively low amplitude, and are the fastest of the four different brainwaves. The frequency of beta waves ranges from 15 to 40 cycles a second. Beta waves are characteristics of a strongly engaged mind. A person in active conversation would be in beta. A debater would be in high beta. A person making a speech, or a teacher, or a talk show host would all be in beta when they are engaged in their work.
The Brainwaves: Ned Herrmann, The Creative Brain
The next brainwave category in order of frequency is alpha. Where beta represented arousal, alpha represents non-arousal. Alpha brainwaves are slower, and higher in amplitude. Their frequency ranges from 9 to 14 cycles per second.
A person who has completed a task and sits down to rest is often in an alpha state. A person who takes time out to reflect or meditate is usually in an alpha state. A person who takes a break from a conference and walks in the garden is often in an alpha state.
The next state, theta brainwaves, are typically of even greater amplitude and slower frequency. This frequency range is normally between 5 and 8 cycles a second. A person who has taken time off from a task and begins to daydream is often in a theta brainwave state. A person who is driving on a freeway, and discovers that they can't recall the last five miles, is often in a theta state--induced by the process of freeway driving. The repetitious nature of that form of driving compared to a country road would differentiate a theta state and a beta state in order to perform the driving task safely.
Individuals who do a lot of freeway driving often get good ideas during those periods when they are in theta. Individuals who run outdoors often are in the state of mental relaxation that is slower than alpha and when in theta, they are prone to a flow of ideas. This can also occur in the shower or tub or even while shaving or brushing your hair. It is a state where tasks become so automatic that you can mentally disengage from them. The ideation that can take place during the theta state is often free flow and occurs without censorship or guilt. It is typically a very positive mental state.
The final brainwave state is delta. Here the brainwaves are of the greatest amplitude and slowest frequency. They typically center around a range of 1.5 to 4 cycles per second. They never go down to zero because that would mean that you were brain dead. But, deep dreamless sleep would take you down to the lowest frequency. Typically, 2 to 3 cycles a second.
When we go to bed and read for a few minutes before attempting sleep, we are likely to be in low beta. When we put the book down, turn off the lights and close our eyes, our brainwaves will descend from beta, to alpha, to theta and finally, when we fall asleep, to delta.
It is a well known fact that humans dream in 90 minute cycles. When the delta brainwave frequencies increase into the frequency of theta brainwaves, active dreaming takes place and often becomes more experiential to the person. Typically, when this occurs there is rapid eye movement, which is characteristic of active dreaming. This is called REM, and is a well known phenomenon.
When an individual awakes from a deep sleep in preparation for getting up, their brainwave frequencies will increase through the different specific stages of brainwave activity. That is, they will increase from delta to theta and then to alpha and finally, when the alarm goes off, into beta. If that individual hits the snooze alarm button they will drop in frequency to a non-aroused state, or even into theta, or sometimes fall back to sleep in delta. During this awakening cycle it is possible for individuals to stay in the theta state for an extended period of say, five to 15 minutes--which would allow them to have a free flow of ideas about yesterday's events or to contemplate the activities of the forthcoming day. This time can be an extremely productive and can be a period of very meaningful and creative mental activity.
In summary, there are four brainwave states that range from the high amplitude, low frequency delta to the low amplitude, high frequency beta. These brainwave states range from deep dreamless sleep to high arousal. The same four brainwave states are common to the human species. Men, women and children of all ages experience the same characteristic brainwaves. They are consistent across cultures and country boundaries.
Research has shown that although one brainwave state may predominate at any given time, depending on the activity level of the individual, the remaining three brain states are present in the mix of brainwaves at all times. In other words, while somebody is an aroused state and exhibiting a beta brainwave pattern, there also exists in that person's brain a component of alpha, theta and delta, even though these may be present only at the trace level.
It has been my personal experience that knowledge of brainwave states enhances a person's ability to make use of the specialized characteristics of those states: these include being mentally productive across a wide range of activities, such as being intensely focused, relaxed, creative and in restful sleep.
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