Neuroanatomy- Visual Field And Reflexes

Front 1

What CN has cell bodies in the Edinger Wesphal nucleus? Where is it located, what mode does it carry and were do it's neurons go?

Back 1

CNIII. Located along side the oculomotor nucleus in the midbrain. Sends pregang PSNS neurons to the ciliary ganglion. From ciliary ganglion, neurons feed the sphincter muscle of iris and ciliary muscle

Front 2

What is the route of the pupillary light reflex?

Back 2

Cell bodies in retinal ganglion cells send both nasal and temporal axons down optic tract to the pretectal region of the midbrain (around PAG and pineal gland). Here they synapse and send ipsilateral and contralateral interneurons around the PAG. Efferent limbs leave from the EW nucleus and pass thru Red Nucleus on way to sphincter mm of iris

Front 3

What is the route of the near reflex?

Back 3

Axons from the ganglion cells in the retina travel down optic tract to the Lateral Genicuate nucleus of the thalamus. After synapsing, axons travel to the striate cortex (synapse) then travel back to the EW/Oculomotor nucleus in midbrain. Efferent limb travel to ciliary ganglion and medial rectus muscle. From ciliary gangion, go to ciliary muscle.

Front 4

What is the route of pupillary dilation reflex (beginning in hypothalamus)?

Back 4

Cell bodies in Hypothalamus send axons down to spinal cord where synapse. Cell bodies in sympathetic area (T1-L2) send a second neuron into sympathetic chain. At level of superior cervical ganglion, neurons synapse and send axons to sweat glands of forhead, smooth mm. of eyelid, pupil, and sweat glands of face

Front 5

What symptoms/clinical signs would you see with a left oculomotor lesion?

Back 5

Dilated left pupil w/ pupillary reflex absent in L. w/light shinned into either eye. Present on R. no matter which eye light shinned into. Near response absent on L. Ptosis on L. Lateral strabismus on L. Upward gaze paralysis on L.

Front 6

What symptoms/clinical signs would you see with a right optic nerve lesion?

Back 6

Blind in that eye. Pupillary light reflex gone on right and consenual pupil reflx gone on left when light shinned into R. eye. Near response IS present

Front 7

What occurs with visual reflexes/field when you have a right post cerebral or middle cerebral artery occlusion?

Back 7

Pupillary light reflex and near response are mantained unless it's a bilateral lesion. On left side, patient is only able to see on right visual field (left hemonomous hemiantopia)

Front 8

A patient comes to you unable to gae upward w/ sluggish or absent pupillary light reflex, but preserved pupillary constrxn to near response, what may have happened

Back 8

Parinaud's syn: pineal gland tumor resulting in pressure on pretectal region (esp. near upward gaze center by superior colliculus)

Front 9

If a patient gets an interruption along the sympathetic tract (on carotic sheath perhaps), what might happen on face?

Back 9

Ptosis due to smooth muscle involvement, miosis (unopposed action of CNIII) and anhydrosis

Front 10

If a patient gets a subdural hematoma resulting in an uncal herniation, what clinic signs show up?

Back 10

Sluggish or absent pupillary reflex with blown pupil. Ptosis. Extraoccular mvmnts less affected. If RF involved-- semicomatose and decr consciousness

Front 11

How do you test to see if a person has an uncal herniation?

Back 11

Test: pupillary light reflex for blown pupil w/o reflex; Babinski response or flaccidity; arousal w/ pin pricking

Front 12

What might cause cortical blindness?

Back 12

compression of the posterior cerebral arteries leading to ischemia of visual cortex

Front 13

Upper visual field is located___ in the cortex and lower visual field is located___?

Back 13

Upper is located posterior in the occipital cortex (also anterior w/ certain cuts). Lower field is superior

Front 14

What happens to the visual field if the right optic tract is cut after the optic chiasm?

Back 14

Left homonymous hemiantopia: cannot see the left visual field of both eyes since nasal fiber cut from contralateral side and temporal fibers cut from ipsilateral side

Front 15

What happens if Meyer's loop is lesioned on one the right side of the brain?

Back 15

Left homonymous superior quadrantic antopia: cannot see out of the superior quadrant of the left side since upper visual field is carried by Meyer's loop

Front 16

What happens if there is a lesion on the left calcrine fissure area?

Back 16

Right homonymous hemiantopia w/ macular sparing.

Front 17

What is the route, branches, and area supplied of the opthalmic artery?

Back 17

first branch off the internal carotid artery emerging from the cavernous sinus. Have a central retinal artery which feeds the ganglion cells, bipolar, and internal part of receptors of retina. Ciliary arteries get the outer parts of the receptors along w/ retinal arteries.

Front 18

What does the anterior choroidal artery feed? What occurs when it is lesioned?

Back 18

Feeds the optic tract and LGN. Lesions cause hemiantopias

Front 19

What does the middle cerebral artery supply? If lesioned, what occurs?

Back 19

Supplies the cortex and visual radiations in parietal lobe. Lesion causes paralysis and hemiantopias

Front 20

What does the posterior cerebral artery supply?

Back 20

Supplies parts of the LGN and the visual cortex.

Front 21

If a person has third nerve palsy, what symptoms do they manifest? What is likely to cause this?

Back 21

Ptosis and extraoccular muscle weakness together. Usually caused by posterior communicating artery aneurism

Front 22

If a person has a dilated pupil w/o light reaction but maintained extraoccular mm. tone, what might be diagnosis? How could you test?

Back 22

Could have tonic pupil from damage to post-gang fibers in ciliary ganglion. Test w/ pilocarpine to see if denervation supersensitivity exists

Front 23

What symptoms would you see w/ bilateral small, unreactive pupils (Argyll Roberston)? What might it be due to and what is a test you might want to run?

Back 23

Light-near dissociation. Could be caused by Syphilis so run VDRL

Front 24

What are the nuclei that light reflex and near reflex go to? What could cause light-near dissociation?

Back 24

Light reflex comes to pretectal nuclei in the dorsal midbrain while near reflex has input into EW nucleus. L-N dissociation caused by Syphilis, diabetes, lesions in midbrain, Adies pupil

Front 25

In a normal person, if you administer 1% percent pilocarpine to they eye, what would you expect to happen?

Back 25

Nothing, no constriction. Constriction would mean CNIII nerve defect

Front 26

In a person w/ Horner's syndrome, how would you distinguish where along the sympathetic chain their defect is?

Back 26

administer hydroxamphetamine. If preganglionic problem the pupil will dilate. If postgang problem, then no dilation will occur

Front 27

What are central and pre-ganglionic causes of Horner's syndrome?

Back 27

Central: stoke, dissection of vertebral artery w/ brain stem. Pre-gang: cervical spine abnormality, neuroblastoma, apex of lung mass