Visual System pathways S2M1

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Visual System pathways S2M1
2011-08-12 10:26:04
Ross S2M1

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  1. What is the pathway of the opthalmic system
    • Retina
    • Optic Nerve
    • Optic Chiasm
    • Optic tract
    • Lateral Geniculate body
    • Suprachiasmatic nucleus
    • Pretectal nuclei
    • Superior colliculus
  2. What is the role of the Pretectum in the opthalmic system
    Reflex control of pupil and lens
  3. What is the role of the superior colliculus in the opthalmic system
    Orienting the movements of the head and eyes
  4. In the mammalian retina besides the conventional rod-cone system, what also exists
    Malanopsin-associated intrinsic (RGC) photoreceptive system which conveys info for Circadian rhythm
  5. Stereo vision
    The eyes see two different pictures, the brain puts them together to give depth perception
  6. What do the right and left cortex see
    Right cortex sees the the left visual feild, and the left the right
  7. What are the clinical signs of the pituitary tumour pressing on the optic chiasm
    • Bitemporal hemianopia (loss of the temporal visual fields)
    • Bitemporal hemianopia is often caused by
    • Chiasma lesion or pituitary adenoma
  8. Where do the retinal ganglion cells end
    Lateral geniculate nucleus
  9. Where is the primary visual cortex
    Around the calcarian fissure in the occipital lobe
  10. What is the difference in what the primary and secondary visual cortex sees and what the associated visual cortex sees (use an apple as an example)
    • 1o & 2o see a green round object
    • Associated cortex fills in the rest
  11. In respect to the associated visual cortex (extrastriate areas) a parietal lesion would present itself how
    There would be a deficit in the "where" pathway (spatial orientation, size, motion)
  12. In respect to the associated visual cortex (extrastriate areas) a temporal lobe lesion would present itself how
    Deficit in the "what pathway" (recognition of color, naming, and face recognition)
  13. In respect to the associated visual cortex, what is the difference in awareness of patients with a Temporal lobe lesion and a Parietal lobe
    • Patients with a temporal lobe lesion are aware that there is a problem and will compensate for it
    • Patients with a Parietal lobe lesion are unaware of their deficit
  14. What portion of the brain is used for facial recognition
    Medial temporo occipital lobe (Fusiform gyrus)
  15. Retrochiasmal lesions have what clinical signs
    Contralateral Homonymous visual deficits (ex. Right field in both eyes)
  16. Loss of blood supply to what arteries would cause a retrochiasmal lesion
    • Posterior cerebral artery
    • Middle cerebral artery
  17. Quadrantanopia
    A loss of sight affecting a quarter or quadrant of the field of vision
  18. Periventricular leukomalacia (PVL)
    • White matter lesion around ventricles
    • Peripheral lower visual field deficits
  19. Temporal epilepsy
    • Very common, can be resistant to antiepileptic medication
    • Performing a lobectomy can fix it
  20. What is the complication with a lobectomy at the anterior temporal lobe
    Contralateral superior quandrantanopia
  21. Anton Syndrome
    When a patient has blindness but fervently believes that they can see. The patient can describe objects they haven't previously seen but in complete error and they are oblivious to it
  22. Occipto-temporal cortical disorder
    • Trouble recognizing objects and naming them
    • But can recognize them buy hearing or touching them
  23. Visual agnosia
    The inability of the brain to recognize familiar objects or faces
  24. What is the effect of a Occipito-parietal lesions
    Trouble seeing things in motion
  25. Autoprosopagnosia
    Person doesn't recognize themselves in the mirror
  26. Prosopagnosia
    • Disorders of face recognition
    • Typically results from bilateral lesions of the lingual and fusiform gyri
  27. Flashing and lightning seen in the eye can be caused by
    Retinal detachment (no pain)
  28. Small flashing in the eye accompanied by pain can be caused by
    Optic neuritis