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Electroencephalography (EEG) – Brainwaves

Electroencephalography (EEG) – Brainwaves. Trauma as a soldier threatened emotional connection between him and his sister, experienced as psychic transmission. After the war he became a psychiatrist and worked on the technology until he obtained first recording in 1924.

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Electroencephalography (EEG) – Brainwaves

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  1. Electroencephalography (EEG) – Brainwaves

  2. Trauma as a soldier threatened emotional connection between him and his sister, experienced as psychic transmission. After the war he became a psychiatrist and worked on the technology until he obtained first recording in 1924. From 1929 to 1938 he published 14 scientific papers investigating EEG in clinical and normal populations. Hans Berger (1873-1941)

  3. WWI German soldier As a soldier in the German Army in first decade of 1900, Berger fell off his horse directly in front of artillery cart and was nearly run over When he returned to HQ, telegram from his father saying his sister had feeling that he had been injured Berger would explore physical means of such psychic transmissions Brain waves were first studied to help explain a psychic experience

  4. He studied blood circulation in brain (1901). He investigated influence of heartbeat, respiration, vasomotor functions, and position of the head and body on brain pulsations measured through an opening (trephined) in the skull, but information was limited and ultimately disappointing. In 1902 he measured electrical activity above skull defects with capillary electrometer; later a galvanometer. Brain activity & psychic action

  5. Berger was fully aware that Richard Caton (1842-1926), a Liverpool surgeon, had succeeded in 1875 in measuring electrical potentials on the exposed cortex of experimental animals (rabbit and monkey). Berger also knew of Polish physiologist Adolf Beck (1891) and Russian physiologist Pravdich-Neminski (1879-1952) who recorded photographic record of the electrical activity of dog’s brain through the skull. Previous Research leading to EEG

  6. 1926 lab Berger's experiments carried on in spare time and utter secrecy. As a diversionary measure he gave public discourses on telepathy, offering hypotheses of wave propagation to explain it. Secrecy

  7. Berger made 73 EEG recordings from his 15y son, Klaus. First frequency encountered was in 10-hertz range, (8 to 12 Hz) which he named alpha (others called the Berger rhythm). After 5 years of investigation, he published his findings. In 1929 he reported how brain waves changed dramatically if subject simply shifts from eyes closed to eyes open state. Furthermore, brain waves also changed when the subject sat quietly with eyes closed "focusing" on solving a math problem. First EEG (1924)

  8. He studied normal subjects and brain-injured, thereby laying the foundation for the application of the technique to clinical technology. In 1937 invited to preside with Adrian at symposium on electrical activity in the nervous system at the Congress of Psychology in Paris. They hailed Berger as the most distinguished of all the visitors. He was ordered by Nazi authorities in 1938 to fire all Jewish employees at his lab. He refused and was forced to retire. He hung himself at his clinic on June 1, 1941 Recognition came late

  9. Electrophysiology • spontaneous activity, • evoked potentials, and • single neuron recordings

  10. MEG

  11. Instrument sensitivity • 102 volts - Wall socket • 10-3 volts - EKG (millivolts) • 10-6 volts – EEG (microvolts)

  12. 10-20 System of Electrode Placement • F = Frontal • P = Parietal • T = Temporal • O = Occipital • C = Central A = Auxiliary • Odd # = Left • Even # = Right

  13. Acquisition

  14. How do you study this?

  15. … manipulate behavioral context, stimulus presentations

  16. Energy (Amplitude) & Speed (Frequency)

  17. Energy distribution by Frequency

  18. Clinical EEG Rhythms

  19. Sleep Stages

  20. Inhibitory forces generate population rhythmicity

  21. Alpha rhythm = idling rhythm, prepared to response, easier to recruit neurons in such states than if in active processing states

  22. Eyes Closed Baseline

  23. Eyes Open Baseline

  24. Role of Topography and “Timing”

  25. Posterior Alpha during Eyes Closed Rest :Normal

  26. Frontal Slowing during Math: Abnormal

  27. Brain (surface) Maps • Normal Abnormal

  28. AUTISM • a neurodevelopmental disorder that impacts cognition and behavior • “Auto” –child is locked within him/herself

  29. Sleep Spindle matures by 3 months of age

  30. 1969 study where spindles in autistics ranged from 10.5-15 Hz

  31. Heartbreak of autism • Lack of reciprocity, little connection with mother • 1 in 10 chance of having another autistic child

  32. 4 times more likely for boys to be autistic than girls

  33. Fully Matured Spindle in 4 month old infant at risk for autism

  34. Perfectly Normal Boy

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