Neurophysiology - Lecture 16 & 17

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Neurophysiology - Lecture 16 & 17
2010-11-04 17:31:57
Neurophysiology Vision

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  1. The distance between two crests or troughs (peak to peak measurement)
  2. Filled with a jelly like fluid, refracts light onto the retina
  3. Where the optic nerve leaves the eye, causes a blind spot
    Optic Disk
  4. Where accomodation occurs
  5. Center of the retina, focused vision, where light falls when looking straight ahead
  6. Located at the center of the macula, dense # of photoreceptors
  7. A fat lens is a result of ciliary muscles ______ and is used to see _____________.
    • relaxing
    • close objects
  8. A flat lens results when ciliary muscles _______ and is used for seeing ___________.
    • contract
    • far objects
  9. As aging occurs the lens _______, so it is harder for the lens to go _______, which impairs _________ vision.
    • stiffens
    • fat
    • near vision
  10. Nearsightedness, also known as ________, is corrected by a ________ lens to reduce refractive power
    • Myopia
    • negative
  11. __________, or farsightedness, is corrected by a ______ lens to add refractive power.
    • Hyperopia
    • positive
  12. This condition is corrected by an asymmetric lens to compensate for the asymmetry of the eye's lens.
  13. Increased fluid pressure in the eye causing optic nerve damage and eventually death resulting in blindness
  14. The cones degenerate, central vision is lost, but peripheral vision remains due to the rods.
    Macular degeneration
  15. Clouding of the lens and the lens must be surgically removed and replaced with a plastic one.
  16. 3 layers of the Retina
    • 1. Ganglion Cells
    • 2. Bipolar Cells
    • 3. Photoreceptors
  17. Ganglion Cells contain
    Amacrine cells
  18. Bipolar Cells contain
    Horizontal cells
  19. Peripheral vision, sensitive to light, high convergence and motion detection
  20. Central vision, sensitive to color, low convergence and fine discrimination
  21. Cones are more concentrated at the _____________
  22. Rods are concentrated more heavily ______________ the fovea
  23. Rods and cones constantly regenerate this protein, because one it changes, it falls off of the receptor
  24. 3 types of cones
    • Red
    • Green
    • Blue
  25. After about __ minutes in the dark, the rods are more sensitive than the cones
  26. On-center and off-center receptive fields ________ boundaries between light and dark.
  27. Ganglion cells responsible for fine detail. Have small receptive fields, sustained APs and color opponent cells
  28. Ganglion cells than are responsible for movement. Have large receptive fields, are sensitive to low contrast and have fast AP.
  29. Red/green type color opponent ganglion cells are ______ while blue/yellow are ________.
    • P-type
    • NonM-nonP
  30. Why do we have parallel processing in the visual system?
    Processing each bit of info sequentially would take too long and would be unreliable. Parallel processing is much faster.
  31. mixed info from both visual fields
    optic nerve
  32. nasal visual fields cross over at the
    optic chiasm
  33. same information from one visual field travels along the
    optic tract
  34. Why do we have binocular vision and what does it allow for?
    Because the visual fields from both eyes overlap, creating depth perception in the center.
  35. Can use two images taken from slightly different angles and present them next to each other, producing depth perception in once focused image
  36. 2 pictures taken from slightly different angles and overlayed. One image is presented to each eye through color filtering glasses, which allows depth perception in a flat field.
    3d stereoposis
  37. Responsible for pupillary light reflex and moves head to orient to a visual image.
    Superior Colliculus
  38. __________ layers take info from P-type while ____________ layers take info from m-type
    • Parvocellular
    • Magnocellular
  39. Lateral Geniculate Nucleus organization (dorsal to ventral)
    P, K, P, K, P, K, P, K, M, K, M, K
  40. The major input to the LGN is the _________ cortex and the rest of the brain.
  41. Project from layer 1 & 2 of LGN to layer IVCalpha
  42. Project from layers 3-6 of LGN to layer IVCbeta
  43. ______ visual cortex cells respond strongly to a given orientation.
  44. _______ visual cortex cells respond strongly to movement in a direction
  45. 5 things the primary visual cortex is responsible for.
    • A complete map of the outside world in the brain
    • Focuses on the middle of vision
    • Focuses on contrast
    • Tuned to straight lines in the environment
    • Highly sensitive to motion and color
  46. In the extrastriate cortex, the _______ is the 'where' pathway, so motion is analyzed.
    ________ is the 'what' pathway, detail and color are analyzed.
    • Dorsal (moves to posterior parietal)
    • Ventral (moves to inferior temporal cortex)
  47. Damage to V4, loss of color vision (only see black and white), subjects describe the world as depressing and food as unappetizing and hard to taste.
  48. The eyes use the amount of light on the retina to help judge if an area is ________. All other colors are then compared to this baseline _______ color.
  49. Inability to identify common items, but may be able to copy drawing of items and draw items from memory
    Visual Agnosia
  50. Inability to recognize faces, including close family and themselves. Damage to IT and the Fusiform Face Area.
  51. Damage to area MT of the brain; loss of ability to perceive motion, though perception of objects is intact
    Motion Agnosia
  52. Perception of movement when none exists
    Induced Motion
  53. Perception of motion in a stationary stimulus after viewing a moving stimulus. Occurs in area MT
    Motion Aftereffect (or Waterfall Illusion)
  54. Biological motion is the perception of motion related to living things. This involves the ________ __________ Sulcus
    Superior Temporal
  55. When shown a still that suggests motion, people remember the motion as being ______ along than it actually is. This activates brain areas ___ and ____
    • further
    • MT and MST
  56. Apparent and real motion occur in _____ & _______ (areas of visual cortex)
    VI and MT