1. The Visual and the occulo-motor system Netta Levin MD PhD fMRI unit,Department of Neurology Hadassah Hebrew-University Hospital Jerusalem, Israel

2. Visual Neuroanatomy Afferent – eye to brain Pupillary reflex arc Efferents – eye movements

3. Cranial nerves

5. Visual Neuroanatomy Afferent – eye to brain Pupillary reflex arc Efferents – eye movements

6. C.N. Ⅲ, Ⅳ & Ⅵ : Ocular nerves CN III: Oculomotor nerve CN IV: Trochlear nerve CN VI :Abducens nerve Visual inspection: ocular alignment, lids Smooth pursuits Saccades Nystagmus 6 cardinal directions of gaze Cranial nerves

7. C.N. Ⅲ, Ⅳ & Ⅵ : Ocular nerves Cranial nerves Extraocular movements (H and X)

8. Extra-Ocular Muscles

9. CN III Innervates Levator, inferior oblique & all recti except lateral rectus Projects ventrally Enters cavernous sinus after crossing PCOM

10. CN III Subnuclei All subnuclei are ipsilateral EXCEPT Levator subnucleus forms a fused central nucleus Superior rectus subnuclei decussate to innervate contralateral superior rectus muscle

11. IS it nuclear or peripheral ? It must be nuclear if Bilateral CN III without ptosis Unilateral CN III with bilateral ptosis BUT Complete bilateral CN III Bilateral ptosis May be either!

12. CN IV Nucleus just caudal and dorsal to III Innervates Contralateral superior oblique Exits brainstem dorsally Longest intracranial course

13. CN VI Origin: ponto-medullary junction Projects ventrally Innervates ipsilateral lateral rectus

15. Cavernous Sinus Site of multiple cranial nerve palsies Vascular Tumor Idiopathic –Tolosa-Hunt

16. Supranuclear control

18. Internuclear Pathways PPRF :Paramedian Pontine Reticular Formation MLF : Medial longitudinal fasciculus

19. Paramedian Pontine Reticular Formation Horizontal Gaze center –Initiates horizontal eye movements Projects to ipsilateral CN VI nucleus Lesions of the PPRF cause ipsilateral gaze palsies

20. MLF Midbrain to cervical spine Composed of interneurons: ipsilateral CN VI to contralateral CN III. fascicle for horizontal gaze and vertical gaze that connects the VI and III nuclear complexes.

21. Damage to the MLF

22. Damage to the MLF+PPRF

23. Visual Neuroanatomy Afferent – eye to brain Pupillary reflex arc Efferents – eye movements

24. Pupillary function - Light reflex ( C.N. Ⅱ & Ⅲ ) Dim lights Fix gaze on opposite wall to eliminate effects of accommodation Shine bright light obliquely into each pupil Look for both direct (same eye) and consensual (opposite eye) reaction Record pupil size and shape Cranial nerves

26. Pupils 1 st Order – Retina to Pretectal Nucleus in B/S (at level of Superior colliculus) 2 nd Order – Pretectal nucleus to E/W nucleus (bilateral innervation!) 3 rd Order – E/W nucleus to Ciliary Ganglion 4 th Order – Ciliary Ganglion to Sphincter pupillae (via short ciliary nerves)

27. Pupillary function Normal pupils are equal in size and shape and are situated in center of iris Pupillary size varies with intensity of ambient light, but at average intensity is ~3-4 mm -Miosis < ~2 mm -Mydriasis > ~5 mm -Anisocoria = pupillary asymmetry Cranial nerves

28. Constricted (mioisis) Sympathetic (pupillodilator) denervation Drugs Pilocarpine Morphine Dilated (mydriasis) Parasympathetic (pupilloconstrictor) denervation Lesion of the third CN Drugs Atropine Cocaine

29. Pupillary function Cranial nerves

30. Visual Neuroanatomy Afferent – eye to brain Pupillary reflex arc Efferents – eye movements

31. Visual acuity Visual fields Fundoscopy Afferent limb of pupillary function Cranial nerves C.N. Ⅱ Optic: vision

32. Hold card at comfortable reading distance Cover 1 eye Glasses on (looking for optic nerve lesion, not refractive error) C.N. Ⅱ Optic: vision Visual acuity Cranial nerves

33. C.N. Ⅱ Optic: vision Visual fields Cranial nerves

34. C.N. Ⅱ Optic: vision Fundoscopy Cranial nerves

36. Optic radiation Occipitalcallosal Optic tract tract Optic nerve nerve

37. How do we divide the visual cortex into separate areas? Retinotopic mapping Functional signature Visual cortex

38. How do we divide the visual cortex into separate areas? Retinotopic mapping Functional signature Visual cortex

40. Retinotopic organization of visual areas.

41. Visual stimuli Polar stimuli

42. Eccentricity mapping: Foveal to Peripheral vision anterior posterior V1 Retinotopic mapping

43. Eccentricity mapping

44. Lesions in the visual pathways Retinal damage Macular degeneration

46. How do we divide the visual cortex into separate areas? Retinotopic mapping Functional signature Visual cortex

47. There are many visual centers Two Visual streams Functional mapping

48. Faces vs. Places processing activation Functional mapping

49. Lesions in the visual pathways Cortical damage Prosopagnosia

50. Prosopagnostic patient Activation within face related region Activation within place related region

52. Visual Impairments

53. Young man presented with the complaint that he cannot see to the left or the right sides of his visual fields while looking straight ahead.

61. Monocular - Binocular Pre–chiasmatic – monocular Chiasmatic / Post-chiasmatic - binocular

62. Non-congruent inferior binocular field defects

64. Congruent partial hemianopia

66. Congruency – Incongruency Posterior lesions are more congruent

67. 70 Y/O female Sudden onset – diplopia, dysphagia -> -> ataxia -> dysarthria -> impaired consciousness EXAM – Somnolent, EOM – disconjugate, Gag – decreased, bilateral Babinsky Visual Fields?

68. Spared binocular macular vision

69. Bilateral PCA stroke (tip of the basilar) Macular Sparing

71. Localizing the lesion Monocular visual field defects indicate lesions anterior to the optic chiasm Bitemporal defects are the hallmark of chiasmal lesions Binocular homonymous hemianopia result from lesions in the contralateral postchiasmal region

72. 18 Y/O male Sudden onset of blindness (following argument with girl friend) Signs of preserved sight Visual fields - tunnel vision

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78. 60 y/o Presenting with confusion Pt denies neurological deficits On exam – –No sensory / motor signs –Confabulations to questions –Visual fields to confrontation – uncooperative

79. 60 y/o Presenting with confusion Pt denies neurological deficits On exam – –No sensory / motor signs –Confabulations to questions –Visual fields to confrontation – uncooperative –Anton Syndrome – Cortical blindness Anosognosia

81. 25 y/o female Headaches for the last month + Transient visual obscurations (TVO’s) + Diplopia (Horizontal? Veritcal?) + Tinnitus Referred by Opthalmologist PMH - Acne

83. 25 y/o female Headaches for the last month + Transient visual obscurations (TVO’s) + Diplopia (Horizontal? Veritcal?) + Tinnitus Referred by Opthalmologist Dx ? Idiopatic Increased Intracranial Hypertension

84. 25 y.o. female New onset of reduced visual acuity and pain with eye movement

85. 25 y.o. female New onset of reduced visual acuity and pain with eye movement On examination Reduced visual acuity Decreased red saturation Relative Afferent Pupillary Defect (RAPD)

86. RAPD

87. Optic neuritis is a disease of the optic nerve, causing acute visual loss. Optic neuritis can be clinically isolated but more often can arise as one of the manifestations of multiple sclerosis

89. VEP

90. Thanks!