Visual Tracts Flashcards
An image focused on the retina will be centered at what structures?
Fovea centralis
Macula lutea
What structure is the location of the blind spot of the retina?
Optic disc, located medial to the macula
What structure does the optic tract terminate in?
Lateral Geniculate Nucleus
Layers 1 and 2 comprise what layers of the LGN?
Magnocellular layers
Layers 3-6 of the LGN comprise what layers that have small receptive fields?
Parvocellular layers
Magnocellular layers receive input from what structures?
Rods
What layers of the LGN are responsive to high-acuity color vision?
Parvocellular layers (Input from cones)
What layers of the LGN do the ganglion cell axons from the temporal retina terminate in?
Ipsilateral layers 2, 3, and 5
What layers of the LGN do the ganglion cell axons of the nasal retina terminate in?
Contralateral 1, 4, 6
What fibers of the optic radiations are received by the superior bank of the calcarine sulcus? What lobe?
Fibers from lower quadrant of contralateral hemifields
Cuneus
What fibers from the optic radiations target the inferior bank of the calcarine sulcus? What part of the occipital lobe?
Fibers from upper quadrant of contralateral hemifields
Lingual gyrus
What fibers form the Meyer loop?
Fibers from upper quadrant of contralateral hemifields
Fibers conveying information from the ____ and ___ originate from central regions of the LGN and pass to caudal portions of the visual cortex.
Macula
Fovea
What visual field deficit can be produced if there is a lesion to the temporal lobe? What visual structure has been damaged?
Superior visual field deficit - damage to Meyer’s loop
What is the function of the visual association cortex? What Brodmann’s areas?
Interpret location, motion, form, color
Brodmann areas 18 and 19 (surround primary visual cortex 17)
Where does the retinal input to the superior colliculus come from?
Select fibers from optic tract that bypass the LGN
What is the function of the superior colliculus?
Spatailly directs head movements and visual reflexes
What is the function of the pretectal/pretectum area?
Pupillary light reflex
Mediates non-conscious behavioral responses to acute changes in light
What is a heteronymous visual field lesion?
Two eyes have non-overlapping field losses
What kinds of visual field deficits are produced when there is damage anterior to the optic chiasm?
Deficit only in ipsilateral eye
What kind of visual field deficits are produced when there is damage at the optic chiasm?
Heteronymous deficits
Damage behind the optic chiasm causes what kind of visual field deficits?
Homonymous deficits
The closer a lesion is to ___, the more congruous it is likely to be.
Visual cortex
Patient presents with inability to name an object that he is seeing, but he recognizes it and knows its use. What is his disorder? This may result from occlusion of what artery?
Associative Visual Agnosia
Posterior Cerebral A.
