visual system part three... from high yield neuro

Question 1

optic chiam contains a few fibers that AREN’T decussating. What?!

Answer 1

Thats right. the TEMPORAL portions of the retina send fibers to chiasm to project to the SUPRACHIASMATIC nucleus of the hypothalamus

Question 2

optic tract contains fibers that go to what 3 places

Answer 2

• ipsilateral LGN
• pretectal nuclei
• superior colliculus

Question 3

LGN receives axons from what 3 places

Answer 3

• contralateral nasal retina
• ipsilateral temporal retina
• layer VI of striate cortex (this is NOT typo)

Question 4

altitudinopia

Answer 4

transection of both lingual gyri that causes two pies in the skies.
aka. can only see the inferior visual field for both sides, both eyes

Question 5

pupillary light reflex: motor nucleus? and ganglion?

Answer 5

edinger-westphal ==> ciliary ganglion to eye via occulomotor nerve

Question 6

how do you get the near/accomodation reflex

Answer 6

• V1 (area 17) projects to visual association cortex (area 19)
• area 19 projects through corticotectal tract to superior colliculus and pretectal nucleus
• those two project to the occulomotor complex

Question 7

what are the three visible parts of the near/accomodation reflex

Answer 7

• pupillary CONSTRICTION
• THICKENING of lens (contract ciliary muscles)
• CONVERGENCE of eyes

Question 8

where is frontal eye field?

what does it control?

Answer 8

brodmann’s area 8 (middle frontal gyrus)

voluntary (saccadic) eye movements

Question 9

where is the occipital eye field?

what does it control?

Answer 9

brodman’s areas 18 and 19

involuntary (smooth) pursuit and tracking

Question 10

where is the subcortical center for lateral conjugate gaze?

Answer 10

abducent nucleus (some also include PPRF)

Question 11

where is the subcortical center for vertical conjugate gaze?

Answer 11

rostral interstitial nucleus of MLF (riMLF) ** in midbrain @ level of posterior commissure