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Human brain
produces electrical signals of various frequencies depending on its
functioning. These signal are transmitted through neurons and ultimately
lead to various mental and physical activities.
Brainwave patterns are
typically grouped into four different categories: Alpha,
Beta, Theta and Delta.
Each of these brainwave patterns is associated with various states of
mind.
What happens
when a reverse process happens ? i.e. instead of being in a particular
state of mind and thereby diagnosing the brainwave corresponding to that
state, if one applies the same frequency signals externally to brain ?
The result is altered state of mind, and so one can in-principle use
brainwaves to achieve altered state of mind e.g. meditative state.
Brainwave Categories:
Alpha Waves It is believed that many creative people are
most of the time in Alpha state than others. Alpha waves
are between 9 and 14 Hz and occur when the body is awake and at
rest, not asleep, and the eyes are closed. You may feel
intellectual relaxation, deep relaxation or meditation when in
Alpha. Alpha brainwave rhythms produce: warm hands and feet,
peaceful feelings, a sense of well-being, improved academic
performance, improved sleep, increased productivity in the
workplace, reduced anxiety and improved immune functioning which
counters the negative affects of Cortisol.
Beta Waves are fast, low amplitude waves of 15 to 30
times per second (Hz). Beta brainwave patterns are generated
naturally when in an awake, focused and alert state of
consciousness. In Beta we experience the stresses of our
day-to-day activities. (e.g. Driving cars, shopping, paying
bills, meeting deadlines.)
Theta Waves are between 4 and 8 Hz and are commonly
referred to as the dream or "twilight" state. Memory development
is enhanced in this state. In the Theta brainwave state, memory
is improved, and access to unconscious material, sudden insight,
free association and creative ideas is increased. Theta is
associated with REM and dreaming states.
Delta Waves are observed when in a sleeping state. Delta
waves are the slowest of brainwaves spanning from 1 to 3 Hz in
frequency. As we fall asleep the dominant brainwave becomes
Delta.
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ScienceDaily (Mar. 31, 2010) —
Forget about crystals and candles, and about
sitting and breathing in awkward ways. Meditation research explores how
the brain works when we refrain from concentration, rumination and
intentional thinking. Electrical brain waves suggest that mental
activity during meditation is wakeful and relaxed (click here to
read more).
Let us try to
understand the Brain Pathology:
Electroencephalography (EEG)
is the recording of electrical activity
along the scalp produced
by the firing of neurons within
the brain. In
clinical contexts, EEG refers to the recording of the brain's
spontaneous electrical activity over a short period of time, usually
20–40 minutes, as recorded from multiple electrodes placed
on the scalp.
Comparison of EEG bands
| Type |
Frequency (Hz) |
Location |
Normally |
Pathologically |
|
Delta |
up to 4 |
frontally in adults,
posteriorly in children; high amplitude waves |
- adults
slow wave sleep
- in babies
- Has been found during
some continuous attention tasks (Kirmizi-Alsan et al.
2006)
|
- subcortical lesions
- diffuse lesions
- metabolic encephalopathy
hydrocephalus
- deep midline lesions
|
|
Theta |
4 – <8 |
Found in locations not
related to task at hand |
- young children
- drowsiness or arousal in
older children and adults
- idling
- Associated with
inhibition of elicited responses (has been found to
spike in situations where a person is actively trying to
repress a response or action) (Kirmizi-Alsan et al.
2006).
|
- focal subcortical
lesions
- metabolic encephalopathy
- deep midline disorders
- some instances of
hydrocephalus
|
|
Alpha |
8 – 13 |
posterior regions of head,
both sides, higher in amplitude on dominant side. Central
sites (c3-c4) at rest . |
- relaxed/reflecting
- closing the eyes
- Also associated with
inhibition control, seemingly with the purpose of timing
inhibitory activity in different locations across the
brain (Klimesch, Sauseng, & Hanslmayr 2007; Coan & Allen
2008).
|
|
|
Beta |
>13 – 30 |
both sides, symmetrical
distribution, most evident frontally; low amplitude waves |
- alert/working
- active, busy or anxious
thinking, active concentration
|
|
|
Gamma |
30 – 100+ |
Somatosensory cortex |
- Displays during
cross-modal sensory processing (perception that combines
two different senses, such as sound and sight) (Kisley &
Cornwell 2006; Kanayama, Sato, & Ohira 2007; Nieuwenhuis,
Yeung, & Cohen 2004)
- Also is shown during
short term memory matching of recognized objects,
sounds, or tactile sensations (Herrmann, Frund, & Lenz
2009)
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- A decrease in gamma band
activity may be associated with cognitive decline,
especially when related the theta band; however, this
has not been proven for use as a clinical diagnostic
measurement yet (Moretti et al. 2009).
|
|
Mu |
8 – 13 |
Sensorimotor cortex |
- Shows rest state motor
neurons (Gastaut, 1952).[16]
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- Mu suppression could be
indicative for motor
mirror neurons working, and deficits in Mu
suppression, and thus in mirror neurons, might play a
role in
autism. (Oberman et al., 2005)[17]
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Wave patterns
Wish to try out some brainwaves ??????????????
You may download some of the brainwaves from http://anupamaholistics.4shared.com
(you must use a headphone to listen to these brainwaves, otherwise it
has no effect, as these brainwaves are binaural beats created by beating
of different frequency sounds in two ears).
OR visit
http://www.bwgen.com/index.htm
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