Brian Disorders

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Brian Disorders

  1. 1. Development of Physiological Influences <ul><li>The brain </li></ul><ul><li>Nerve function </li></ul><ul><li>Visual perception </li></ul><ul><li>Brain localization </li></ul><ul><li>Psychophysics </li></ul>
  2. 2. A. The Brain <ul><li>Australopithecus africanus </li></ul><ul><li>Trephining </li></ul>
  3. 3. Egyptians <ul><li>Threw away brain when mummifying </li></ul>
  4. 8. Greek Doctors: Are There Animal Spirits in There? <ul><li>dissected brains and optic nerves; brain is organ of thought </li></ul><ul><li>the soul is in the fourth ventricle and the &quot;animal spirits&quot; (intellectual, motor system) are in the brain itself (cerebrum) </li></ul>
  5. 9. Galen’s Cell Doctrine <ul><li>Galen localized the mind to the ventricular system of the brain </li></ul>
  6. 10. <ul><li>First cell: imaginativa (imagination) and &quot;fantasia&quot; (fantasy) </li></ul><ul><li>Second cell: &quot;aestimativa&quot; (judgment), &quot;cognitativa&quot; (thought) and &quot;ratio&quot; (reason) </li></ul><ul><li>Third cell: &quot;memorativa&quot; (memory) </li></ul>
  7. 11. Pre-Renaissance <ul><li>“ Animal Spirits” </li></ul>
  8. 12. Renaissance - da Vinci <ul><li>da Vinci’s system </li></ul><ul><li>Anterior ventricle: 'intelletto' (intellect) and 'imprensiva’ </li></ul><ul><li>Middle ventricle: 'volonta' (will) and 'senso comune’ </li></ul><ul><li>Posterior ventricle: 'memoria' (memory) </li></ul>
  9. 14. Renaissance - Descartes <ul><li>Agreed with Galen about ventricles </li></ul><ul><li>Nerves are tubes with valves connected at one end to the ventricles (animal spirits) to muscles at the other end (hydraulic theory) </li></ul>
  10. 16. B. Nerve function (electricity view)
  11. 17. Whytt's (b. 1714) Reflex <ul><li>Reflexive contraction of pupil to light </li></ul><ul><li>Reflexes were involuntary and depended on spinal cord </li></ul><ul><li>Nervous tissue contained a sentient principle </li></ul>
  12. 18. Galvani-Volta Debate
  13. 19. <ul><li>Luigi Galvani (b. 1737) claimed that he discovered animal electricity (electrical body fluid) </li></ul><ul><li>Count Alessandro Volta (b. 1745) said that all that happened was that the frog conducted static electricity </li></ul>
  14. 21. <ul><li>&quot;Galvanic skin response&quot; – GSR </li></ul><ul><li>Volta….. Volts, Voltage </li></ul><ul><li>Giovanni Aldini provided basis for a novel written by a famous writer………... </li></ul>
  15. 22. du Bois-Reymond (b. 1818) <ul><li>Discovered the action potential </li></ul><ul><li>He or Galvani the &quot;Father of Electrophysiology“? </li></ul>
  16. 23. Sir Charles Bell (b. 1774) <ul><li>Experiments with rabbits </li></ul><ul><li>Francois Magendie – experiments with puppies  </li></ul>
  17. 24. Bell-Magendie Law <ul><li>dorsal roots of spinal nerves bring in sensory information </li></ul><ul><li>ventral roots carry motor fibers down to the muscles </li></ul>
  18. 25. Johannes Muller (b. 1801) <ul><li>Directly aware only of the activity in our nerves, not external reality </li></ul><ul><li>Doctrine of specific nerve energies - same stimulus applied to different sensory nerves results in different sensations </li></ul>
  19. 26. C. Research on Visual Perception
  20. 27. Hermann von Helmholtz (b. 1821) <ul><li>Medicine, physics, math, psychology, music, philosophy </li></ul>
  21. 28. <ul><li>&quot;On the conservation of force“ </li></ul><ul><li>Metabolism </li></ul><ul><li>Determined wavelength of ultraviolet light </li></ul><ul><li>Optics </li></ul><ul><li>Theory of velocity of air in open tubes (acoustics) </li></ul><ul><li>Thermodynamics (Law of conservation of energy) </li></ul>
  22. 29. Contributions to Psychology <ul><li>Measuring the speed of the nerve impulse (REACTION TIME) </li></ul><ul><li>Young-Helmholtz trichromatic color theory </li></ul><ul><li>Place theory of pitch perception </li></ul>
  23. 30. Ewald Hering (b. 1834) <ul><li>Opponent-process theory of color perception </li></ul>
  24. 32. Hering Illusions
  25. 33. Hering bow
  26. 34. Jan Purkinje (b. 1787) <ul><li>Shift from cone to rod vision in twilight </li></ul><ul><li>Purkinje effect in stars - red source will cease to be visible before the yellow or white source </li></ul>
  27. 35. D. Brain Localization
  28. 36. Phrenology
  29. 37. Franz Gall (b. 1758); his pupil Spurzheim <ul><li>The mysterious “Miss Leisler” </li></ul><ul><li>&quot;Neither sin nor friends will ever leave me.&quot; </li></ul>
  30. 38. Gall’s Work on Nervous System <ul><li>Nervous system is like a tree </li></ul><ul><li>Distinction between gray matter (neurons) and white matter (axons) </li></ul><ul><li>CNS fibers terminate in the cortex, not the medulla </li></ul><ul><li>Identified origins of cranial nerves I-VIII </li></ul><ul><li>Pyramidal tracts crossing brain hemispheres </li></ul>
  31. 39. Gall’s Claim: <ul><li>Mental activities localized in the cortex </li></ul><ul><li>Wanted to develop a functional anatomy and physiology of the brain, as well as a revised psychology of personality </li></ul><ul><li>Led to theories concerning localization and cranioscopy </li></ul>
  32. 40. The System of Organology <ul><li>Brain is organ of the mind </li></ul><ul><li>Brain is a collection of organs representing various propensities, sentiments, faculties </li></ul><ul><li>Size of each organ indicates its power </li></ul><ul><li>Skull conforms to brain's shape </li></ul><ul><li>Mind's functions located in different places in the brain </li></ul>
  33. 41. How Many Faculties of Mind? <ul><li>Gall sez 27 </li></ul><ul><li>Spurzheim sez 37 </li></ul>
  34. 42. Napoleon’s & Descartes’ Heads
  35. 43. Phrenology taken over by Quacks <ul><li>Employment </li></ul><ul><li>Marriage prospects </li></ul><ul><li>Children's prospects </li></ul><ul><li>1920's - “The Psychograph” </li></ul>
  36. 44. Problems with Phrenology <ul><li>Arbitrary choice of faculties </li></ul><ul><li>Observations not fitting in explained away </li></ul>
  37. 45. Contributions of Phrenology <ul><li>Established brain as the source of mind </li></ul><ul><li>Mental functions localized in the brain </li></ul>
  38. 46. Pierre Flourens (b. 1794) <ul><li>&quot;An Examination of Phrenology&quot; 1824 </li></ul><ul><li>Ablation technique- removal of one of six separate areas of brain </li></ul>
  39. 47. 6 Different Brain Functions <ul><li>Cerebral hemispheres - willing, judging, memory, seeing, hearing </li></ul><ul><li>Cerebellum - motor coordination </li></ul><ul><li>Medulla oblongata - mediation of sensory/motor functions </li></ul><ul><li>Corpora quadrigemina (inferior/superior colliculi) - vision </li></ul><ul><li>Spinal cord - conduction </li></ul><ul><li>Nerves - excitation </li></ul>
  40. 48. Flourens vs. Gall <ul><li>Flourens’ approach reflected localization, but he stressed the common action of the various parts </li></ul><ul><li>Emphasis on the common unity of the entire system </li></ul>
  41. 49. “Recovery of Function” <ul><li>Also observed recovery of mental function over time - forerunner of &quot;neural plasticity&quot; </li></ul>
  42. 50. Brain Localization: The Story of Phineas Gage
  43. 51. <ul><li>Sept. 13, 1848 - Vermont - a deadly day for Phineas </li></ul><ul><li>Iron rod entered under left cheek, exited through top of head, landed 30 yards away. </li></ul><ul><li>Dr. John Harlow </li></ul><ul><li>MRI analysis by Damasio shows damage in ventromedial region on left side of brain </li></ul>
  44. 55. http://www.offoffoff.com/theater/2002/phineasgage.php3
  45. 56. Language Localization in Brain
  46. 57. Paul Broca (b. 1824) <ul><li>Patient named Leborgne </li></ul><ul><li>Autopsy showed lesion to 3rd convolution of left frontal lobe </li></ul><ul><li>Concluded this area important for speech articulation </li></ul>
  47. 58. Broca’s Brain!
  48. 59. Karl Wernicke (b. 1848) <ul><li>Damage in top left temporal lobe causes poor language comprehension (Receptive aphasia) </li></ul>
  49. 60. Psychophysics – the Beginning of Psychology?
  50. 61. Ernst Weber (b. 1795) <ul><li>Investigated 2-point thresholds for touch </li></ul><ul><li>Jnd's investigated for various stimuli </li></ul><ul><li>Jnd's vary by a constant ratio called “Weber Fraction” </li></ul><ul><li>First to quantitatively measure the mind? </li></ul>
  51. 62. Gustav Fechner (b. 1801) <ul><li>&quot;Elements of Psychophysics&quot; 1860 </li></ul>
  52. 63. <ul><li>The term “Psychophysics” coined - science of studying the relation between the physical and the mental (stimulus and sensation) </li></ul><ul><li>Fechner's Law </li></ul><ul><li>Devleoped: method of limits, method of constant stimuli, method of average error (adjustment) </li></ul>

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