Embed Size (px)
Citation preview
Six seconds of data, recorded 5 minutes apart
Electroencephalography Electroencephalography FirstFirst recording of electrical fields of animals, recording of electrical fields of animals,
Caton (1875); humans, Caton (1875); humans, BergerBerger (1929). (1929). Berger named it Berger named it electroencephalogram (EEG)electroencephalogram (EEG). . From 1929 to 1938 he published 14 scientific From 1929 to 1938 he published 14 scientific
papers on the EEG under the same title "Über das papers on the EEG under the same title "Über das Elektroenkephalogram des Menschen". Elektroenkephalogram des Menschen".
What can be measured:What can be measured:• spontaneous activity spontaneous activity • evoked potentialsevoked potentials• bioelectric events produced by single neuronsbioelectric events produced by single neurons
Hans Berger (1873-1941)Hans Berger (1873-1941)
He became interested He became interested in the possibility of in the possibility of brain transmission in brain transmission in response to a psychic response to a psychic experience during war.experience during war.
After the war, he After the war, he became a psychiatrist became a psychiatrist and worked on the and worked on the technology until he technology until he obtained first recording obtained first recording in 1924. in 1924.
From 1929 to 1938 he From 1929 to 1938 he published 14 scientific published 14 scientific papers investigating papers investigating EEG in clinical and EEG in clinical and normal populations.normal populations.
Brain waves were first studied to Brain waves were first studied to help explain a psychic experiencehelp explain a psychic experience
WWI German soldierWWI German soldier
As a soldier in the As a soldier in the German Army in first German Army in first decade of 1900, Berger decade of 1900, Berger fell off his horse directly fell off his horse directly in front of artillery cart in front of artillery cart and was nearly run overand was nearly run over
When he returned to HQ, When he returned to HQ, telegram from his father telegram from his father saying his sister had saying his sister had feeling that he had been feeling that he had been injuredinjured
Berger would explore Berger would explore physical means of such physical means of such psychic transmissionspsychic transmissions
First EEG (1924)First EEG (1924) Berger made 73 EEG recordings Berger made 73 EEG recordings
from his 15y son, Klaus. from his 15y son, Klaus. • First frequency encountered First frequency encountered
was in 10-hertz range, (8 to was in 10-hertz range, (8 to 12 Hz) which he named 12 Hz) which he named alpha (others called the alpha (others called the Berger rhythm).Berger rhythm).
After 5 years of investigation, After 5 years of investigation, he published his findings. he published his findings.
In 1929 he reported how brain In 1929 he reported how brain waves changed dramatically if waves changed dramatically if subject simply shifts from eyes subject simply shifts from eyes closed to eyes open state. closed to eyes open state. Furthermore, brain waves also Furthermore, brain waves also changed when the subject sat changed when the subject sat quietly with eyes closed quietly with eyes closed "focusing" on solving a math "focusing" on solving a math problem. problem.
MEGMEG
Electroencephalography Electroencephalography INTRODUCTIONINTRODUCTION The first recording of the electric field of the human brain was made by the German psychiatrist The first recording of the electric field of the human brain was made by the German psychiatrist
Hans Berger in 1924 in Jena. He gave this recording the name Hans Berger in 1924 in Jena. He gave this recording the name electroencephalogram (EEG)electroencephalogram (EEG). . (Berger, 1929).(From 1929 to 1938 he published 20 scientific papers on the EEG under the same (Berger, 1929).(From 1929 to 1938 he published 20 scientific papers on the EEG under the same title "Über das Elektroenkephalogram des Menschen".) title "Über das Elektroenkephalogram des Menschen".)
spontaneous activity, spontaneous activity, evoked potentials, and evoked potentials, and bioelectric events produced by single neurons. bioelectric events produced by single neurons.
Spontaneous activitySpontaneous activity is measured on the scalp or on the brain and is called the is measured on the scalp or on the brain and is called the electroencephalogram. The amplitude of the EEG is about 100 µV when measured on the scalp, and electroencephalogram. The amplitude of the EEG is about 100 µV when measured on the scalp, and about 1-2 mV when measured on the surface of the brain. The bandwidth of this signal is from under about 1-2 mV when measured on the surface of the brain. The bandwidth of this signal is from under 1 Hz to about 50 Hz, as demonstrated in Figure 13.1. As the phrase "spontaneous activity" implies, 1 Hz to about 50 Hz, as demonstrated in Figure 13.1. As the phrase "spontaneous activity" implies, this activity goes on continuously in the living individual. this activity goes on continuously in the living individual. Evoked potentialsEvoked potentials are those components of the EEG that arise in response to a stimulus (which may are those components of the EEG that arise in response to a stimulus (which may be electric, auditory, visual, etc.) Such signals are usually below the noise level and thus not readily be electric, auditory, visual, etc.) Such signals are usually below the noise level and thus not readily distinguished, and one must use a train of stimuli and signal averaging to improve the signal-to-distinguished, and one must use a train of stimuli and signal averaging to improve the signal-to-noise ratio. noise ratio. Single-neuronSingle-neuron behavior can be examined through the use of microelectrodes which impale the cells behavior can be examined through the use of microelectrodes which impale the cells of interest. Through studies of the single cell, one hopes to build models of cell networks that will of interest. Through studies of the single cell, one hopes to build models of cell networks that will reflect actual tissue properties. reflect actual tissue properties.
Eyes Closed BaselineEyes Closed Baseline
Eyes Open BaselineEyes Open Baseline
Alpha burst is rewardingAlpha burst is rewarding
AutismAutism
Silent Snow, Secret SnowSilent Snow, Secret Snow
Temple GrandinTemple Grandin
Personal applicationPersonal application
Current EEG ApplicationsCurrent EEG Applications
CLINICALCLINICAL Epilepsy (1930s)Epilepsy (1930s) Sleep (1940s)Sleep (1940s) Patient monitoring, Patient monitoring,
anaesthesiaanaesthesia Head injury Head injury
assessmentassessment Neurological Neurological
assessment (AEP)assessment (AEP) NeurotherapyNeurotherapy Psychiatric Psychiatric
assessmentassessment
SCIENTIFICSCIENTIFIC AttentionAttention WorkloadWorkload Circadian rhythmsCircadian rhythms CognitionCognition Learning & MemoryLearning & Memory
Future EEG ApplicationsFuture EEG Applications
Lie DetectionLie Detection Product preferenceProduct preference Interpersonal Interpersonal
synchronysynchrony Firefox and other Firefox and other
brain-computer brain-computer interfaces (BCI)interfaces (BCI)
……
