Lacey Electroencephalogram Final

8/2/2019 Lacey Electroencephalogram Final

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Electroencephalogram

(EEG): Measuring BrainWaves


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Function of EEG The EEG uses highly conductive silver electrodes coated with

silver-chloride and gold cup electrodes to obtain accuratemeasures use impedance device to measure effectiveness,resistance caused by dura mater, cerebrospinal fluid, and skullbone

Monopolar Technique : the use of one active recording electrodeplaced on area of interest, a reference electrode in an inactivearea, and a ground

Bipolar Technique : the use of two active electrodes on areas ofinterest

Measures brain waves (graphs voltage over time) throughelectrodes by using the summation of many action potentials sentby neurons in brain. Measured amplitudes are lessened withelectrodes on surface of skin compared to electrocorticogram


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Sodium-Potassium Pump The mechanism within neurons that creates action

potentials through the exchange between sodium andpotassium ions in and out of the cell

Adenosine Triphosphate (ATP) provides energy forproteins to pump 300 sodium ions per second out ofthe cell while simultaneously pumping 200 potassiumions per second into the cell (concentration gradient)

Thus making the outside of the cell more positively

charged and the neuron negatively charged This rapid ionic movement causes the release of action

potentials


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History Richard Caton (1875)localization of sensory functions with

monkeys and rabbits Hans Berger (1924) first EEG recording done on humans

- described alpha wave rhythm and its suppression compared to beta

waves - acknowledged alpha blockade when subject opens eyes

William Grey Walter influenced by Pavlov and Berger, further

developed EEG to discover delta waves during sleep (1937) andtheta waves (1953)


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Alpha Wave Characteristics:

- frequency: 8-13 Hz-amplitude: 20-60 V

Easily produced when quietly sitting in relaxed position with eyesclosed (few people have trouble producing alpha waves)

Alpha blockade occurs with mental activity-exceptions found by Shaw(1996) in the case of mental arithmetic,archery, and golf putting


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Beta Waves Characteristics:

-frequency: 14-30 Hz-amplitude: 2-20 V

The most common form of brain waves. Are present during mentalthought and activity


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Theta Waves Characteristics:

-frequency: 4-7Hz-amplitude: 20-100V

Believed to be more common in children than adults Walter Study (1952) found these waves to be related to

displeasure, pleasure, and drowsiness

Maulsby (1971) found theta waves with amplitudes of 100V inbabies feeding


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Delta Waves Characteristics:

-frequency: .5-3.5 Hz-amplitude: 20-200V

Found during periods of deep sleep in most people Characterized by very irregular and slow wave patterns

Also useful in detecting tumors and abnormal brain behaviors


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Gamma Waves Characteristics:

-frequency: 36-44Hz-amplitude: 3-5V

Occur with sudden sensory stimuli


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Less Common Waves Kappa Waves:

-frequency: 10Hz-occurred in 30% of subjects while thinking in Kennedyet al.(1948)

Lambda Waves:-amplitude: 20-50V-last 250 msec, related to response of shifting visualimage-triangular in shape

Mu Waves:-frequency: 8-13Hz-sharp peeks with rounded negative portions (7% ofpopulation)


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Alternative NeuroimagingTechniques Positron Emission Technique (PET):

- picture image of brain giving information about glucose andoxygen structures in the brain, blood flow, and blood volume in thebrain

-advantage: compare cross-sections of brain regionssimultaneously-disadvantage: findings may be caused by inhibitory neurons

Functional Magnetic Resonance Imaging (MRI):-picture image of anatomical structures, derived from magneticimaging-allows for measurement of blood oxygen concentration, blood

flow, and blood volume-advantage: see ongoing changes as well as strong spatialresolution, and quick/effective data collection


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Alternative Methods (cont) Biomagnetism:

-Measures magnetic activity given off by the brain-Super conductive quantum interfering device (SQUID)-disadvantage: very difficult to pick up these small magneticmeasures due to environmental magnetic forces

Magnetoencephalogram (MEG):-similar to EEG in that it combines the activities of millions ofneurons-advantages: no reference electrode, some currents can only befound magnetically, scans field patterns of brain allowing forsimultaneous area activity

-disadvantage: data not as clear and device is very susceptible tonoise


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The EEG and its ManyApplications


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Research and Application

Psychological Research

Neurological Research

Medical Research Educational Research and Application

Therapeutic Application

Occupational Application


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How Effective is the EEG?

A great deal of controversy has surrounded the use ofEEG in tests for such topics as Intelligence and mentalperformance.

Criticism, however, is familiar to any aspect of research

in the scientific world. As a result of the critiques and of technological

advances, procedures, measurements, and results havebecome more precise, reliable, and valid.

In order to the best and most accurate information fromEEGs, though, researchers agree that furtherinvestigation and ongoing research is necessary.


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The EEG has become a widely used andsuccessful research tool

It is a practical candidate that offers validmeasurement

It contributes objective information that can beeasily viewed and measured

It is a versatile system that allows for a diverseapplication of the information it provides


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Hemispheric Asymmetries & Hemispheric

Lateralization/ Specialization

Desynchronization


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Right and Left Brain Characteristics

Right Brain: Spatial processing Musical tasks

Left Brain: Verbal processing Mathematical skills

** Emotions have also been correlated with differentialhemispheric processing (Davidson, Schwartz, Saron, Bennettand Goleman, 1979)

(Andreassi, John L., Psychophysiology: Human Behavior and Physiological Response, 2000).


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Stimulus Complexity

An investigation was conducted by Berlyne andMcDonnel (1965) in order to study the effects ofthe complexity of the stimulus/stimuli on the

EEG alpha wave. Their hypothesis wasconfirmed as a result of EEG records thatdemonstrated that higher levels of complexityproduced longer alpha desynchronization

periods.



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Tasks of Vigilance and Attention

In order to study attention ability Ray and Cole(1985) investigated participants intake andrejection of stimuli. The results showed that alpha power was greater in

the right hemisphere during rejection. Beatty, Greenberg, Deibler, and OHanlon

(1974) found that EEG readings demonstratedthat suppression of theta activity and rhythmhelped to better maintain vigilance whileperforming tasks.



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Hypnosis, Imagery, Meditation andPerception

Traditionally, the lines between the four greatly

related mind states were not very clear. Research

conducted with the use of EEG, however, has enabled

researchers to draw more distinct lines between each of

the topics, and to study the distinct characteristics of each

of them.


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Hypnosis

EEG during hypnosis has contributed to the knowledge that it isnot a stage of deep sleep, rather a modification of the wakingstate

MacLeod, Morgan and Lack (1982) conducted a dream task studyduring hypnosis using EEG.

The results demonstrated a shift from greater left hemisphere

activity, to right in highly hypnotizable participants, and no suchshift in low hypnotizable participants.

A related study conducted by DePascalis and Perrone (1996)revealed that participant pain ratings decreased when ananalgesic state was suggested during hypnosis

The EEG records showed a decrease in EEG amplitude in the right

hemisphere during the above mentioned condition.



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Imagery

Gale, Morris, Lucas and Richardson conducted a studyin 1972 in which imagery was measured on a vividnessscale, while the occipital area was recorded using EEG. The results of the EEG showed a definite decrease in Alpha

activity during all but one of the imagery tasks.

Williamson and Kaufman (1989) later integrated theMagnetoencephalograpy (MEG) to study suppression ofalpha activity in the visual cortex during mental imagery.



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Meditation

Results from a study conducted by Elson, Hauri,and Cunis (1977) were collected and based onEEG information. The EEG readings from the meditating group

demonstrated stable alpha and theta activity, andnone fell asleep.

The EEG records from the non-meditating group, onthe other hand, revealed K-complexes and sleep

spindles. A total of six of the participants from thegroup fell asleep.



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Sensation, Perception and EEG

Studies have indicated that our perceptionand sensations may have substantialeffects on mood and emotional states.


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EEG records showed that sound sensitivity was lowerduring periods of alpha activity than during non-alphaactivity.

In 1998 Martin evaluated previous information aboutthe effect of odor on EEG and mood, conducting two ofhis own studies, and was able to report a variety ofeffects. He believed that previous investigations produced different

results due to a difference in EEG recording. The results of his own carefully controlled experiments

supported a correlation between odor and EEG activity.**Real food odors, such as chocolate, were linked to

extremely low theta levels and received the highest participantratings for relaxing effects and pleasantnessrevealing the

capability of odors to change EEG activity.



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The Awesome EEG

It is plain to see that EEG has offered a numberof great advances in research. It hasdemonstrated its versatility and usefulness in themany diverse areas that it has been utilized.

From therapeutic endeavors, and enhancingeducational efforts, to offering information andinsight that has helped to improve pilots,conductors, and drivers vigilance performance,as well as strengthening the base of general

knowledge in a way that has helped to improveour everyday lives .


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Conditioning of The EEG

&Sleep and The EEG


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Conditioning of the EEG


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Classical Conditioning (EEG):

Pairing of conditioned and unconditioned stimuli to warrant aconditioned response.

EEG recordings found changes in neural activity with the presenceof CS (Condition stimulus).

In EEG experiments that involve conditioning:

-alpha blocking occurs with respect to the CS after manypairing

of a CS and US.

-The UR (unconditioned response) is a natural alphablocking process.

-Classical conditioning Is usually done with the participantbeing asleep.


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CS US UR }Natural alpha blocking , the CS alonecannot

(light) (tone) (no response) sustain alpha blocking

after several pairings

CS US UR

(light) (tone)

CS

US

UR }Trying to sustain CS alphablocking W/

(light) (tone) multiple pairings of US.

CS US UR

(light) (tone)

finally

US CR } The US has now been shaped to create the CS.

CS CR } The new CS creates the same CR as the previous

CS. The new CS can now generate alphablocking on its own.


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Operant Conditioning (EEG)Can it be done?

Done while participant is awake.

Studies include work with people suffering from seizures (epileptics),and their progress.

Studies w/ operant conditioning shows results of other disorders

being alleviated (biofeedback). I.E. Migraines Studies are being done to see if people can control which brain

waves they can produce (alpha and theta) with the onset of a signalor tone.

Most people could not produce alpha and theta waves on command

w/o the signal or tone being given Researches tried to alter mood with alpha waves as well.

All in all, operant conditioning of EEG has been deemed possible


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Non-contingent stimuli (operant conditioning):

Expectancy effects:

- Subjects who were led to believe that they enhanced

alpha were actually able to control alpha better than

those who believed they suppressed alpha.

Biasing effects:- Experimenters expectations were found to influence EEG alpha

measures in the direction of the expectation.

Controls:

- Controls are effective and necessary in non-contingent stimulation studiesin

operant conditioning studies.A. increase in alpha could be due to randomness or non-contingent

stimuli.


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Sleep and The EEG


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Sleep and EEG:

Sleep studies are very hard to conduct.

- Takes many nights to conduct a full study

- Patience is a must both participants and experimenters

Benefits of sleep studies:

- Better understanding in studies involving

A. Human performance

B. Behavior

C. Well-Being


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Sleep and EEG contd:

Sleep studies began in the 1800s

1930s EEG recording machines began to make an appearance.

Todays sleep laboratories have many different kinds of

physiological machines and recorders such as: EEG

EOG (electroculogram)

EMG (electromyogram)

Rectal temperature

Respiration(Any measurements made by these machines are called-

Polysomnograms)


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Sleep and EEG contd:

Different stages of sleep and their respective brain waves:

Stage 1: Low voltage random EEG activity (2-7 Hz)

Stage 2: Irregular EEG pattern/negative-positive spikes (12- to 14- Hz) Also characterized with sleep spindle and K-complexes that could occur every few seconds.

Stage 3: Alternative fast activity, low/high voltage waves and highamplitude delta waves or slow waves (2 Hz or less).

Stage 4: Delta waves

Stage REM (Rapid eye Movement): episodic rapid eye movements, low v

voltage activity.

Stage NREM: All stage combined, but not including REM or stages that maycontain REM.

The K-complex occurs randomly in stage 2 and stage 3

The K complex is like an awaken state of mind in that is associated with aresponse to a stimulus that one would experience while awake.


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EEG and Dreaming:

REM was discovered in 1953 by Aserinsky and Kleitman.

REM was observed as fast eye movements that moved in manydirections while a person was asleep.

REM varied in amplitude and lasted 1 second or less. Studies showed that people remember dreams 75% (60-90%) more

when waken during REM sleep, If not woken during REM sleepdreams are only remembered 7% of the time.

NREM dreams are described as being less active and less vivid

Therefore, there are both qualitative and quantitative differenceswhen discussing REM and NREM sleep.


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Dream Studies:

The first dream studies were interested in:

Changing dream content

Drugs and their effects on dreaming

Pre-sleep stimulation and dreaming

Dream content with respect to patients that had differentpsychiatric disorders


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REM Dreaming:

Most early research was concerned with lucidity of REM Dreaming.

Meaning one could shape what they dreamed in choosing what theywould dream about.

Come to the realization that one is dreaming

High amplitude EEG alpha waves.

Higher in the beginning of REM, and lower in end of REM.

Higher amplitude waves are also characterized of bizarre, and

emotional dreams.

Ongoing lucid studies are being conducted to see if lucid contentcome from prelucid dreaming.

Questions the relationship between REM alpha waves and Lucidity


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Deep sleep and Responsiveness:

Light sleep (stages 1&2)

Deep sleep (stages 3&4)

Sleep is cyclicalMeaning that one will usually go from light sleep to deep

sleep back to light sleep again.

The whole cycle take about 1 and hours (90 min.)

Stage 3 and 4 are hard to obtain, due to light sleep

occurring more towards the end of a sleep cycle.


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EEG brain waves in the Sleep Cycle:


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Sounds and sleep:

Studies found it was more difficult to wake up a person duringlatter stages of sleep, even with very loud sounds.

Fire alarm study:

Researchers looked at how long it would take for someone ina certain stage of sleep to turn off the aversive stimulus(Alarm).

They found People in stage 1 sleep were more likely to turn

off the aversive stimulus quicker than all other stages.Researchers also found that meaningful stimuli awakened

people quicker than non-meaningful stimuli.


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Work and Exercise and how it effectssleep EEG: (Kripke, Cook, and Lewis 1976)

Work (hospital employees):

- Hospital employees experience a reversal in the sleep-

wakefulness

cycle (biological effects).

- Duration of each stage of sleep was usually shorter.

- Stage 1 sleep in hospital employees was generally longer thantypical

stage 1 sleep in normal sleepers.

Work (night shift- permanent):

- Have better body temperature regulation, and more stable sleep

patterns.


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Work schedule and sleep contd:

Hospital workers actually fall asleep if put on a rotating schedule

(10pm 6am)Sleep during daytime hours takes longer, than nighttime

hours.

Daytime sleepers (permanent night shift workers) havereduced REM sleep.


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Exercise and Sleep EEG: Horne and porter(1975)

There are differences between afternoon and morning exercise.

Exercise conditions do not help one to fall asleep easier.

Relaxation techniques help people to fall asleep easier (Brownman andTepas, 1976).

Afternoon exercises produce increased slow-wave sleep/stages 3 and4.

(85 minutes bike ride)

Same amount of exercise in morning had no effects.

Stages 3 and 4 are known and restore and repair stages.

However, people that exercise do not experience longerdurations of sleep in stages 3 and 4 or SWS (Brownman and

Tepas, 1976). Bunnel, Bevier, and Horvath found that exercising to the pointof exhaustion increased slow-wave sleep, but decreased REM.

Therefore daytime activity can increase stage 3 and 4sleep/SWS as long as it is intense in duration.


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Sleep Deprivation:

Three different kinds: (Naitoh, 1975) Total sleep deprivation

missing one or more sleep periods

Partial sleep Deprivation missing a section of the sleep cycle

Differential Sleep Deprivation Wakening a person during different random points in a sleep cycle based on

EEG signs of particular stage


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Total Sleep Deprivation: (Woodward and Nelson, 1974)

Studied army men who experienced 2 sleep cycles lost

Effects:

Memory impairment (short term memory)

Increased irritableness

Attention deficits (micro lapses)

Lack of motivation

EEG showed an increase in slow wave sleep in recovery


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Partial Sleep Deprivation: (Webb & Agnew, 1974)

Done over a 60 day periods consisting of 5 hours of sleepeach night.

Experienced an increase in Stage 2 and 4 sleep.

REM decreased by 25%

Vigilance decreased as experiment progressed.

Conclusion for partial sleep deprivation:

6 hours is needed to be vigilant

Major behavioral differences will occur (see above)


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Differential Sleep Deprivation: (Moses, Johnson,Naitoh and Lubin, 1975)

One study looked at deprivation of REM/Stage 4 sleep deprivationand total REM sleep deprivation.

REM/Stage 4 study -2 nights vs. Total REM sleep -3 nights:

Needed more arousals than second experiment to keep them fromentering stage 4 sleep.

Concluded that Stage 4 has more importance than REM sleep due tosleep loss.


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Sleep onset, difficulties with EEG wavelocation, experimental difficulties:

Alpha waves vary person to person, makes it hard to locate in stage1 sleep

K-complexes and sleep spindles are giveaways of a person beingasleep

People dont respond to certain tones during certain stages of sleep.

People might not hear the tone (hearing impaired)- Hearing testsshould be down to rule out this confounding variable.

People that have insomnia (elderly men and women)/misperceptionetc.

Insomnia causes SWS abnormalities Researchers would like a behavioral measure as an additional

indicator of a person being asleep, but none exists.

An ideal machine would measure finger muscle depression


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Sleep onset, difficulties with EEG wavelocation, experimental difficulties contd:

EEG and thermoregulartory system patterns;

Shows that drop in rectal temperature, signifies SWS issustained.

More studies must be done to confirm this.


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Summary of EEG:

Conditioning exercises prove that Alpha wave control may bepossible.

Discovery of REM made it possible for further investigations intosleep studies and various parts of sleep.

The strength of a stimulus has an impact on the outcome of a study.

Learning may occur during stage 1 & 2 of sleep when material ismeaningful

Dreams vary in content and emotions

Daytime sleep differs from nighttime sleep on a number of levels

Confounding variables are important in eliminating before

conduction an EEG study. Selective deprivation vs. Insomnia

Biological effects on sleep


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References:

Andreassi, J. L. (2000). Psychophysiology: Human Behavior &Physiological Response (4thed.) Mahwah, New Jersey:Lawrence Erlbaum Associates, publishers.

Sleep Holsitconline.com. (1998-1999). The different stages ofsleep [Chart]. World Wide Web. Retrieved September 10th, 2006,from

http://holisticonline.com/Remedies/Sleep/sleep_stages-1- 4NREM.htm

(1996, October 11). The Electro-Physiology Of Sleep. RetrievedSeptember 9th, 2006, fromhttp://ourworld.compuserve.com/homepages/dreamthemes/

a ge31.html
http://holisticonline.com/Remedies/Sleep/sleep_stages-1-http://ourworld.compuserve.com/homepages/dreamthemes/ahttp://ourworld.compuserve.com/homepages/dreamthemes/ahttp://ourworld.compuserve.com/homepages/dreamthemes/ahttp://ourworld.compuserve.com/homepages/dreamthemes/ahttp://holisticonline.com/Remedies/Sleep/sleep_stages-1-http://holisticonline.com/Remedies/Sleep/sleep_stages-1-http://holisticonline.com/Remedies/Sleep/sleep_stages-1-http://holisticonline.com/Remedies/Sleep/sleep_stages-1-


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References contd:

Cell Biology. (2005, January 11). Cell Biology. RetrievedSeptember 9th, 2006, fromhttp://www.nurseminerva.co.uk/cell.html

Wikipedia. (2006, September 9). Electroencephalography[Chart]. World Wide Web. Retrieved September 8th, 2006,

from http://en.wikipedia.org/wiki/Electroencephalogram

Wikipedia. (2006, September 10). Hans Berger. World WideWeb. Retrieved September 9, 2006, from

http://en.wikipedia.org/wiki/Hans_berger
http://en.wikipedia.org/wiki/Electroencephalogramhttp://en.wikipedia.org/wiki/Electroencephalogram

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