Burns Vision III

  1. LGN- axons
    are monocular
  2. LGN- Magnocellular (M) layers
    • 1,2
    • projections from large (magnocellular) RG cells
    • movt, location, contrast
  3. LGN- Parvocellular (P) layers
    • 3-6
    • projections from small (prvocellular) RG cells
    • color, form, fine visual detail (incl object recognition)--> facial recognition
  4. Projections from primary cortex--> many, including extra-striate cortical segments
    • extra-striate cortical segments:
    • Ventral (temporal)-parvocellular modalities
    • Dorsal (parietal)- magnocellular modalities
  5. R optic n lesion
    • blind in R eye
    • Monocular blindness
  6. optic chiasm lesion
    • loose temporal vision in both eyes
    • Bitemperal hemianopsia
  7. R optic tract/LG lesion
    • loose L side vision in both eyes
    • Contralateral homonymous hemianopsia
  8. R Superior radiation lesion
    • loose inferior VF on L side in both eyes (L inf quad out)
    • Contralateral (homonymous) inferior quadrantanopsia
  9. L Inferior radiation lesion
    • loose R superior VF in both eyes (R sup quad is out)
    • Contralateral (homonymous) superior quadrantanopsia
  10. R occiptial cortex
    • L VF out in both eyes with macular sparing
    • Contalateral homonymous hemianopsia with macular sparing (similar to optic tract lesion)
  11. other pathways other than the retino-geniculo-calcarine pathway:
  12. • Retino-collicular pathways
    • – Projections to the superior
    • colliculus
    • • Retino-pretectal pathways
    • The pupillary light reflex
    • • Retino-hypothalamic pathways
    • – Control of circadian rhythms
  13. Retino-collicular pathways
    • rapid reflex to external stim
    • aff: retina, prima visu cortex, somatosens system, auditory sytem, etc
    • eff: cervical SC (tectospinal tract), pulvinar, reticular formation, inf colliculus
  14. Retino-pretectal pathways
    • pupillary reflex, consensual
    • retina->pretectum->Edinger-Westphal (pregang parasym, BILATERAL)
  15. Retino-hypothalamic pathways
    • circadian rhythms
    • retina->suprachiasmatic nucl->paraventricular hypoth neurons->intermediolateral (sympathetic) spinal neurons-> cervical ganglion-> pineal glands-> melatonon release
Card Set
Burns Vision III
Burns Vision III