Brain and Behavior

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Author:
courtney3672
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13595
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Brain and Behavior
Updated:
2010-04-08 16:14:29
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Central Visual Pathways
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Exam II
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  1. The optic nerve is formed from the axons of the ____ and passes through the optic canal into the ______.
    • retinal ganglion cells
    • middle cranial fossa
  2. As the optic nerve is an extension of the brain, it is surrounded by the ___ and is bathed in ____.
    • meninges
    • CSF
  3. The four destinations of the fibers of an optic nerve are:
    • 1. Lateral geniculate nucleus
    • 2. Superior colliculus
    • 3. Pretectal area
    • 4. Hypothalamus
  4. The retina is divided into a _____ hemiretina, medial to the fovea, and a ____ hemiretina, lateral to the fovea. .
    • nasal
    • temporal
  5. Each of the four hemiretinas is further divided into a ___ and ____quadrant. Each quadrant is supplied by a corresponding branch of the ______ artery
    • dorsal and ventral
    • central retinal
  6. The right half of the visual field projects on the ___ hemiretina of the right eye and the _____ hemiretina of the left eye.
    • nasal
    • temporal
  7. The inferior half (or quadrant) of the visual field projects onto the ____ half (or quadrant) of the retina.
    superior
  8. Damage to the inferior half of the retina causes a loss in the ____ half of the visual field. Damage to the nasal half of the retina causes a loss in the temporal visual field.
    • superior
    • temporal
  9. The optic nerves come together to form the _____ just anterior to the pituitary gland.
    optic chiasm
  10. The nasal retinal fibers (of each eye) cross the midline in the ___ to reach the _____ optic tract
    • chiasm
    • contralateral
  11. The nasal fibers carry the ____ visual field of the respective eyes.
    temporal
  12. The temporal retinal fibers do not cross in the chiasm and maintain a ___ position in the optic nerve, the optic chiasm, and the optic tract. The temporal retinal fibers carry the ___ visual field of the respective eyes.
    • lateral
    • nasal
  13. Retinal fibers carrying left visual field information (of both eyes) end up in the ___ optic tract.
    right
  14. A pituitary tumor compressing the fibers crossing in the chiasm will produce a lesion of the fibers from the ___ portions of each retina, resulting in a loss of information of the ____ visual fields of both eyes; thus, ______
    • nasal
    • temporal
    • bitemporal heteronymous hemianopsia
  15. The optic tracts pass around the cerebral peduncles to reach the ___.
    lateral geniculate bodies
  16. One could say that retinal fibers carrying left visual field information end up in the ___optic tract.
    right
  17. A lesion of an optic tract often results from a vascular accident involving the ____.
    anterior choroidal artery
  18. A lesion of the central visual pathways beyond the optic chiasm ALWAYS involves the __ visual field and ALWAYS involves the __ visual field of both eyes.
    • contralateral
    • same/ homonymous
  19. Most of the fibers of an optic tract terminate in ___. Some fibers pass around the lateral geniculate nucleus, enter the brachium of the ___ and terminate on neurons in the ____ or the ___. Some post-chiasmatic fibers terminate in the____.
    • a lateral geniculate nucleus
    • superior colliculus
    • superior colliculus
    • pretectal area
    • hypothalamus
  20. The lateral geniculate nucleus (7) is a six layered nucleus, laminated so that layers 1,4, and 6 receive ___ retinal fibers from the ___ eye and layers 2,3, and 5 receive ___ retinal fibers from the ___ eye.
    • nasal
    • contralateral
    • temporal
    • ipsilateral
  21. Each layer of the lateral geniculate nucleus contains a full representation of the viewed object and each part of the image is registered in the adjacent part of each layer. The visual image now has a ____ representation.
    horizontal
  22. The horizontal image in the LGN results from axons from the __ part of the retina terminating on neurons in the __ part of the lateral geniculate nucleus.
    • lower
    • lateral
  23. A lesion of the lateral geniculate nucleus often results from a vascular accident involving the ___ or ____.
    thalamogeniculate or anterior choroidal arteries
  24. The visual field loss resulting from a lesion of the lateral geniculate nucleus would be __ and ____. (comparable to a lesion of the optic tract)
    contralateral and homonymous.
  25. The neurons of the lateral geniculate nucleus project their axons to the ____ in the ___.
    primary visual cortex in the occipital lobe
  26. The optic radiations (geniculocalcarine tract) initially travel rostrally through the posterior limb of the ___. The fibers then bend posteriorly behind the ____and are there called the ____ part of the internal capsule.
    • internal capsule
    • lentiform nucleus
    • retrolenticular
  27. The optic radiations divide into two bundles after they pass beyond the _____ part of the internal capsule. One bundle, ____, carrying one half of the fibers from the lateral geniculate
    nucleus, loops forward into the temporal lobe.
    • retrolenticular
    • the loop of meyer
  28. The Loop of Meyer carries fibers corresponding to fibers in the _____ retinal quadrants-- which corresponds to the _____ visual field quadrants.
    • inferior
    • upper contralateral
  29. Fibers in the optic tract and lateral geniculate nucleus carry __ of each visual field; and now, in the optic radiations, the half fields are further divided into __ quadrants.
    • one half
    • two
  30. The upper portion of the optic radiations carrying a
    ___ visual field quadrant, takes a more direct route around the ___ to get to the primary visual cortex.
    • contralateral lower
    • posterior horn of the lateral ventricle
  31. A typical lesion of the optic radiations involves only the upper or lower fibers of the optic radiations and results in a loss of _____ of the visual field; _____ .
    • 1/4
    • contralateral, quadrantic, homonymous anopsia
  32. A lesion of the optic radiations typically results from a vascular accident involving the cortical branches of the ____. As the two bundles of the optic radiations proceed posteriorly around the lateral ventricle, the visual image is ___ and ____.
    • middle cerebral artery
    • upside down and vertical
  33. The two bundles of optic radiations come closer together in the ____part of the ____and form a very thick, broad, heavily myelinated bundle which passes to the ___.
    • posterior
    • occipital
    • primary visual cortex
  34. At the location where the two bundles of optic radiations are closest together, a single lesion can affect all of the optic radiation fibers and produce a ___,____ ______.
    contralateral, homonymous hemianopsia.
  35. The optic radiations terminate in a narrow band of cortex above and below the ______ in
    the ______ .
    • calcarine fissure
    • occipital lobe
  36. The upside-down image is registered in the primary visual cortex so that (for a human figure) from head to waist is registered in the ___ and from waist to feet in the _____. The narrow primary visual cortex is ____.
    • lingual lobule
    • cuneus
    • Brodmann's area 17
  37. ______ of optic radiations as they penetrate deeper into the cortex gives the primary visual cortex a striped appearance and it is therefore also called the ____.
    • demyelination
    • striate cortex
  38. The visible stripe where the myelin drops off in the primary visual cortex (layer IVb) is called ___.
    the Line of Gennari
  39. The primary visual cortex is organized into functional columns in which all cells in a straight line
    perpendicular to the ____ have similar properties.
    pia mater
  40. All cells in a column which respond particularly to one eye instead of the other are called ___ columns.
    ocular dominance
  41. The areas of the occipital lobe around the primary visual cortex are ___ and are heavily interconnected with area 17.
    Brodmann areas 18 and 19
  42. Areas __ and___ are secondary and tertiary visual association areas. Information about the visual image is conducted from area __ to areas __ and __ for further integration (color, 3-D, etc.)
    • 18 and 19
    • 17, 18 and 19
  43. Information from the cone cells of the macula of the retina are found __ placed and ___ represented in all structures in the central visual pathways.
    • centrally
    • bilaterally
  44. The ____ image is often not involved in incomplete lesions because of its central location. sparing.
    macular
  45. Macular sparing even in large lesions because:
    The macula also has a very disproportionate representation in the primary visual cortex. This often results in macular sparing, as even very large lesions around the calcarine fissure do not cover the entire macular area. Another suggestion for macular sparing is that the macular region of the primary visual cortex receives a dual arterial supply from the calcarine artery and cortical branches of the middle cerebral artery.
  46. A lesion of the primary visual cortex often affects the upper bank (___) or lower bank (_____) of the primary visual cortex and would therefore only affect ___ of the primary visual cortex on a side. Thus, such a lesion, often resulting from a vascular accident involving the calcarine artery (a branch of the posterior cerebral artery) would result in a ____ , upper or lower, homonymous, ______ anopsia with______.
    • cuneus
    • lingual gyrus
    • 1/2
    • contralateral
    • quadratic
    • macular sparing
  47. Fibers from each occipital lobe pass through the ___ of the corpus callosum to the opposite occipital cortex. This bilateral representation is thought to aid in producing _____.
    • splenium
    • binocular vision
  48. Fibers from each occipital lobe pass to the __ and ___ lobes and are believed to be involved in the interpretation of movement or color and form, respectively.
    parietal and temporal lobes
  49. All areas of the cerebral cortex are interconnected by _____. Thus, all lobes receive some input from the occipital lobe.
    long and short association fibers
  50. Deficits in the visual system are usually referred to as ___.
    visual field defects
  51. Loss of a part of a visual field is an ___.
    anopsia
  52. Total loss of vision in the one eye is called ___
    amaurosis
  53. Loss of vision in the temporal halves of the visual field of both eyes is called ___.
    bitemporal hemianopsia
  54. Loss of vision in the opposite half of the visual field of both eyes is called ___.
    contralateral homonymous hemianaopsia
  55. Loss of vision in the upper quadrant of the visual field of both eyes on the opposite side is called ___.
    left (contralateral) upper homonymous quadrantic anopsia
  56. Partial loss of vision in the lower quadrant of the visual field of both eyes on the opposite side is called ____.
    contralateral lower homonymous quadrantic anopsia with macular sparing
  57. Partial loss of vision in the upper quadrant of the visual field of both eyes on the opposite side is called___.
    contralateral upper homonymous quadrantic anopsia with macular sparing

  58. Lesions in area 1 marked would cause what type of visual defect?
    amaurosis of the right eye-- total vision loss

  59. Lesions in area 2 would cause what type of visual defect?
    • bitemporal hemianopsia
    • (loss of vision in the temporal halves of the visual field in both eyes)

  60. Lesions in area 3 would cause what type of visual defect?
    • left contralateral homonymous hemianopsia
    • (loss of vision in the opposite half of the visual field in both eyes)

  61. Lesions in area 4 would cause what type of visual defect?
    • left contralateral upper homonymous quadrantic anopsia
    • (loss of vision in the upper quadrant of the visual field of both eyes on the opposite side)

  62. Lesions in area 5 would cause what type of visual defect?
    left contralateral lower homonymous quadrantic anopsia with macular sparing

    (partial loss of vision in the lower quadrant of the visual field of both eyes on the opposite side.)

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