Some science behind the scenes
It is well known that the brain is an electro-chemical 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.
Delta waves are high amplitude brain waves with a frequency of 1-4 Hertz usually associated with slow-wave sleep. Delta wave activity occurs most frequently during stage 4 non-rapid eye movement sleep accounting for 50% or more of the EEG record during this stage. Large amounts of delta wave activity are not common in healthy adults during the waking state. However multiple studies have indicated the presence of increased delta activity in adults during states of “intoxication or delirium and those diagnosed with dementia or schizophrenia”. And spiritual experience.
Here the brainwaves are of the greatest amplitude and slowest frequency. 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.
Theta rhythms are brain waves with a frequency of 4-8 Hertz and involve many neurons firing synchronously, in the hippocampus and through the cortex. Theta activity can be observed in adults during some sleep states, as well as in states of quiet focus (meditation, for example). These rhythms are associated with spatial navigation and some forms of memory and learning, especially in the temporal lobes.
Theta brainwaves are typically of even greater amplitude and slower frequency. 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 motorway, and discovers that they can't recall the last five miles, is often in a theta state--induced by the process of motorway 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 motorway 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 ideas that can occur during the theta state are often free flow and “occur without censorship or guilt” [fantasy!!]. It is typically a very positive mental state.
Alpha waves are electromagnetic oscillations in the frequency range of 8–12 Hz (ELF radio waves) arising from synchronous and coherent (in phase / constructive) electrical activity of thalamic pacemaker cells in the human brain. Alpha waves are predominantly found to originate from the occipital lobe [see below] during periods of waking relaxation with the eyes closed. Conversely alpha waves are attenuated with open eyes as well as by drowsiness and sleep.
They are thought to represent the activity of the visual cortex in an idle state. Occipital alpha waves during periods of eyes closed are the strongest brain signals of the EEG. They usually can be detected with the naked eye.
Where beta represents arousal, alpha represents non-arousal. Alpha brainwaves are slower, and higher in amplitude. 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.
Mu waves are electromagnetic oscillations in the frequency range of 8-13 Hz and appear in bursts of at 9 - 11 Hz. Mu wave patterns arise from synchronous and coherent (in phase/constructive) electrical activity of large groups of neurons in the motor cortex (central scalp). They are thus of a similar frequency to alpha waves but occur in a different region of the brain.
Beta wave, or beta rhythm, is the term used to designate the frequency range of brain activity above 12 Hz (12 transitions or cycles per second). They are divided into three groups:
- High Beta Waves (19Hz+);
- Beta Waves (15-18Hz);
- and Low Beta Waves (12-15Hz).
Beta states are the states associated with normal waking consciousness. Low amplitude beta waves with multiple and varying frequencies are often associated with active, busy, or anxious thinking and active concentration. Rhythmic beta with a dominant set of frequencies is associated with various pathologies and drug effects. For instance, beta activity can be accentuated by sedative-hypnotic drugs such as benzodiazepines or barbiturates. It can also be absent or reduced if the patient underwent cortical damage.
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. 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.
Gamma waves are is the term used to designate the frequency range of brain activity between about 24 Hz and up to about 70Hz. They are associated with perception and consciousness. Gamma waves are manifest at 24 Hz, however, higher level cognitive activities occur when lower frequency gamma waves suddenly double into the 40 Hz range. Research has shown gamma waves are continuously present during low voltage fast neocortical activity (LVFA), which occurs during the process of awakening and during active rapid eye movement (REM) sleep.
Overall - 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.
Or get inspiration via a spiritual experience.
This time can thus 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.
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