Neuro Exam2.txt

ciliary ganglion (contraction=miosis)

superior cervical ganglion (contraction=mydriasis)

reduced ability to focus on near objects (because of reduced elasticity of lens with aging)

choroid branches (branch of opthalmic artery, branch of internal carotid)

central artery of retina (branch of opthalmic artery, branch of internal carotid)

rhodopsin

cone opsin

• light activates rhodopsin (or cone opsin)
• rhodopsin interacts with transducin and phosphodiesterase
• conversion of cGMP to 5'cGMP
• decrease in number of open cGMP-gated sodium ion channels
• photoreceptors hyperpolarize as sodium ion channels close

• the cells depolarizes
• (the opposite happens when the light hits the surrounding photoreceptors)

• the cell hyperpolarizes
• (the opposite happens when light hits the surrounding photoreceptors)

• large size
• also called ''m'' cells
• input from rod and cone bipolar cells
• large receptive field
• mostly in peripheral retina

• medium size
• also called ''p'' cells
• input from cone bipolar cells
• smaller receptive field
• mostly in central retina

• small size
• also called ''w'' cells
• not clinically relevant

• SCN (suprachiasmatic nucleus) of hypothalamus
• receives projections from ganglion cells with melanopsin
• target of retinal ganglion cells

• target of retinal ganglion cell axons
• helps control eye movements
• sends projections to pulvinar nucleus of thalamus

• target of retinal ganglion cell axons
• involved in pupillary light reflex
• receives projections from ganglion cells with melanopsin

• target of retinal ganglion cells
• vision

• layers 1-2
• large cells
• input from alpha ''m'' ganglion cells
• rod and cone input

• layers 3-6
• small cells
• input from beta ''p'' ganglion cells
• primarily cone input

1,4,6

2,3,5

• branches of opthalmic artery (of internal carotid)
• central artery of retina (or opthalmic artery)-distal CNII

branches of anterior communicating artery and ACA

anterior choroidal artery (of internal carotid)

thalamogeniculate artery (of PCA)

calcarine artery (of PCA)

branches of MCA

calcarine artery (middle cerebral artery also supplies blood to primary visual cortex at posterior occipital region)

• expanded outer band of Baillerger
• wide layer IV
• Brodmann area 17, striate cortex, V1

• granule: IV
• simple: II, III, V, VI
• complex: II, III, V, VI

• granule: concentric center-surround (spots, rings)
• simple: simple (bars)
• complex: complex (bars)

• alpha ''m'' ganglion cells
• layers 1 and 2 of LGN
• area 17 of occipital lobe
• area 18 of occipital lobe
• middle temporal lobe
• area 7a of parietal lobe

• beta ''p'' ganglion cells
• layers 3-6 of LGN
• area 17 of occipital lobe
• area 18 of occipital lobe
• area 19 of occipital lobe
• area 37 of temporal lobe

visual field deficit

loss of one half of a visual field

loss of one quarter of a visual field

deficit in the same part of the visual field for each eye

deficit in a different part of the visual field for each eye

ipsilateral blindness in one eye

• deficit in visual field surrounded by normal vision
• typically in the center of the visual field
• irregular lesion of macula lutea
• or compression of optic nerve

• detachment of the pigment epithelium from the photoreceptor layer
• if detachment more than a few days there can be permanent damage of photoreceptors from lack of blood flow

destruction of crossing fibers at optic chiasm (most commonly due to pituitary tumor)

destruction of lateral aspect of optic chiasm (most commonly due to aneurysm of internal carotid artery)

• destruction of optic tract, LGN, optic radiation, or primary visual cortex
• (for optic tract: most commonly from occlusion of anterior choroidal artery, for LGN: most commonly from occlusion of thalamogeniculate artery, for primary visual cortex: more complicated)

occlusion of calcarine artery (sparing happens because branches of MCA also supply posterior occipital lobe)

destruction of Meyer's loop

• retinal ganglion fibers
• pretectal area nerve fibers
• Edinger-Westphal nuclei
• ciliary ganglia
• pupillary sphincter muscle

• hypothalamus nerve fibers
• C8-T1 of spinal cord (symp. pregang.)
• SCG (symp. post.)
• pupillary dilator muscle (contraction)

• 1. convergance of eyes due to contraction of medial rectus muscles by nerve fibers from oculomotor nuclei
• 2. pupillary constriction by nerve fibers from ciliary ganglia
• 3. thickening of lens (contraction of ciliary muscles) by nerve fibers from ciliary ganglia

• depth perception,
• lack of stereopsis: defect in formation of ocular dominance columns

abnormal visual stimulation during early developement

deviation of one or both eyes

cloudy lens

• inability to recognize object even though object is perceived
• lesion in visual association cortex (Brodmann areas 18,19)

• lesion in right temporal lobe
• patient can perceive a face and recognize it as a face but can not distinguish one face from another