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Meditation: The Journey Home
by Martin Wuttke
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Meditation and the Brain
by Martin Wuttke
Researchers have been studying the effects of meditation on the brain
and body for over 50 years. One area of interest is the electroencephalograph
(EEG) which is the measurement of the electrical activity of the brain
(brain waves). The EEG is a direct indicator of states of consciousness
and brain function and can be used to determine the effects of meditation
on the brain. Different types of meditation produce different effects
measured by the EEG but research has identified an important finding
that appears in both Tibetan and Kriya yoga advanced meditators: as
compared to non-meditators and other types of meditation, there is
a significant increase in high frequency activity (referred to as
gamma) in the frontal lobes of the brain common to both types of meditation.
The frontal lobes are the seat of the brains executive functions such
as concentration, focus, motivation, goal directed behavior, impulse
control, and higher order reasoning. From an evolutionary standpoint,
the frontal lobes were the last to develop, giving the human brain
the ‘hardware’ for higher order intelligence. Other studies
also reveal that the thickness of this region is actually greater
in meditators versus controls.
In addition, EEG studies on Kriya yoga meditators
have identified the following:
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- There is a decrease in Alpha activity as
Theta increases
This occurs with deeper meditation states and correlates with the
emergence of theta brain waves as inner awareness is increased. Theta
states in meditation are also associated with creativity and intuitive
insight. Also correlating with theta is awareness of normally unconscious
levels of the mind where the patterns and drives that influence our
conscious mind and behaviors can be observed. With continued meditation
practice the Meditator learns to dispassionately view the contents
of this level and neutralize any negative tendencies (samskaras in
Sanskrit).
- There is an increase in the EEG’s frequency called Beta activity
Beta brain waves are associated with activation and therefore, increased
activity of brain locations where it is measured. In meditators this
is found in brain pathways regulating attention, focus and concentration.
In addition, when a Meditator has experiences that have a blissful
or ecstatic component there is a large burst of beta in the left frontal
lobe of the brain; an area associated with emotional regulation, positive
mood and affect. With continued practice, the activation of this area
of the brain contributes to feelings of well-being and emotional contentment
that many meditators report.
- No alpha blocking to stimuli
Alpha brain waves indicate stillness and the brain in ‘neutral’.
Normally, alpha activity is ‘blocked’ when the brain is
activated by a stimulus. In meditators alpha remains present, and
non-reactive regardless of external stimuli. In essence the reactive
pathways in the brain are quieted and the sense, or location of influence
shifts from an outer to an inner cause. This shift correlates with
improvement in the immune systems function and greater regulation
in both under and over acting immune problems.
- There is an overall increase in resting alpha
amplitude and wider distribution throughout brain regions after meditation
vs. before
A marker in the EEG of advanced meditators is that Alpha brain waves
are more powerful and cover larger areas of the brain post meditation.
From a functional perspective this indicates a quiet and clear mind.
It also indicates more efficient use of energy and therefore greater
stamina, endurance and mental capacity.
- Samadhi with increased amplitude high frequency
activity known as Gamma
This is the aforementioned Gamma activity; indicating a heightening,
or magnification, of consciousness. Gamma is also a ‘binding
rhythm’. When it appears in the EEG the brain is connecting
many different areas, binding them together, so that the whole brain
is involved in the processing of perception. This is the mechanism
that is crucial to learning and understanding. The presence of Gamma
apparently relates to the gradual emergence of superconscious energies.
This brings a greater awareness of oneself and like a spotlight it
is impartial. In other words, Gamma exposes both the positive and
negative aspects of our personal beliefs, behaviors and attitudes.
Hence, the Meditator has the opportunity to neutralize negative aspects.
In advanced meditators Gamma is more pronounced than in normals both
during meditation and after. This finding has generated a great deal
of scientific interest because of the potential to quantify higher
states of consciousness from a neurologic perspective.
Findings such as these have generated a new field of study: Neurotheology.
From this perspective, the human brain is the medium through which
consciousness (God) is expressed. And according to esoteric teachings,
the nervous system must undergo systematic refinement in order to
process higher and more expanded states of consciousness. Therefore,
it may be that the presence of Gamma is an indicator of this refinement
process because it means that the brain has increased its capacity
to accommodate greater amounts of awareness. This would also provide
an explanation for the fact that our spiritual awakening comes from
the development of our own innate capacities and that spiritual disciplines
such as meditation, yoga, and various contemplative traditions are,
in effect, methods that systematically direct and facilitate this
refinement process.
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SIDEBAR FOR TECHNICAL EXPLANATION:
Frequency is a measurement of the oscillations, or the cycles per
second also called Hertz (Hz), of the brain waves. This electrical
activity is hypothesized to emerge from vast aggregates of neurons
as they communicate and process information. The source of this activity
is considered to be the postsynaptic changes in electrical potential
along the membrane of the dendrites. These changes are the result
of the highly complex interchange of neurotransmitters in synaptic
junctions between neurons. Both excitatory neurotransmitters that
produce arousal and inhibitory neurotransmitters that decrease arousal
are involved in the production of this electrical activity called
the EEG.
Delta is the slowest frequency of brain wave activity. Delta is measured
from .5 to about 4 cycles per second. Delta is only seen as the dominant
rhythm in the adult EEG in the deep sleep state that occurs within
the first two hours of the sleep cycle. If it is dominant in the waking
state in an adult, it could indicate some type of abnormality. Serotonin
is the neurotransmitter involved with delta rhythm and the appropriate
regulation of our deep, rejuvenate, delta sleep cycle.
The next brainwave bandwidth is Theta. Theta occurs between 4 and
8 cycles per second. Theta in the adult EEG can indicate drowsiness
and can also indicate some abnormalities. Sometimes people with head
injuries will show excessive Theta activity either at the sight of
the injury or other areas of the brain. Theta has also been found
to be outside the norm in some children and adults with ADD and ADHD
and sometimes in children with learning disabilities. Theta dominance
can also be indicative of a certain meditative state where the individual
is on the threshold of awareness of the normally subconscious and
unconscious levels of the mind. Theta is associated with the neurotransmitter
GABA and acts like a natural tranquilizer to counter stress chemicals
in the brain. The temporal lobes, which help govern the frontal and
parietal lobes of the brain, regulate emotions and memory and are
the primary locations for GABA.
The next bandwidth is Alpha. The mental state of Alpha is similar
to putting the clutch in before shifting the gears; it is a holding
pattern. Alpha predominance essentially represents a brain that is
quiet and at rest. Alpha ranges from 8 to 12 cycles per second. Alpha
also regulates the efficiency of the brains processing and thinking
speed and is associated with levels of the neurotransmitter acetylcholine
in the parietal lobes.
Beta is between 13 cycles per second up to over 30 cycles per second.
Low frequency Beta, between 13 and 15 cycles per second, has also
been referred to as "sensory motor rhythm" and it appears
to be a very important rhythm. When this rhythm is present in the
EEG, it has the ability to organize and coordinate many pathways in
the brain. It indicates quieting of the processing of incoming sensory
information with the appropriate motor response. Sensory-motor rhythm
is found to be very high in persons adept in Hatha Yoga while performing
postures. Beta waves ranging from 15 to 20 hertz indicate external
awareness and heightened states of attention. The neurotransmitter
dopamine, which is responsible for our ‘drive’, energy
and motivation is regulated by the frontal lobes and is associated
with Beta. From 20 to 30 hertz, too much Beta activity can indicate
states of hyper-arousal, anxiety or panic. However; from approximately
35 hertz on, this can be a very different indicator in the brain of
the advanced meditators and is called Gamma. Gamma is considered in
these cases to be evidence of ‘being more conscious’. |
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