Term
| What 3 things are required for a working visual system? |
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Definition
optical system (need good optics)
phototransduction (rods and cons-focus image on retina)
Computation (*LARGEST part, ~1/3 of brain required for full visual capability) |
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Term
| Where do most visual information go in the brain? |
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Definition
| back of the head to primary visual cortex in occipital lobe |
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Term
| A lot of the brain is _______ (it is important in localizing tumors and lesions) |
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Definition
| visual (problems with visions=tumors and lesions) |
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Term
| Where do most of the information from the retina go to? |
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Definition
| LGN (lateral geniculate nucleus) and then to primary visual cortex for vision |
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Term
| Where would information of the retina go for saccades (shifts in gaze)? |
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Definition
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Term
| What is the major target of retinal ganglion cells for circadian rhythms (adjusting sleep patterns to light and dark)? |
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Definition
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Term
| What is the major target of retinal ganglion cells for pupillary light reflex (shine light, they get smaller)? |
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Definition
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Term
| What is the major target of retinal ganglion cells for stabilizing gaze (otherwise, it would look like blair witch project)? |
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Definition
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Term
| Only about 10% of retinal ganglion cells do not terminate in the __________________. |
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Definition
| Lateral Geniculate Nucleus (LGN). |
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Term
The Retina -> LGN -> Cortex pathway is known as what 2 other systems?
What is this responsible for? |
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Definition
geniculostriate or thalamocortical system
conscious vision |
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Term
| Primary Visual Cortex is in the __________ Lobe. |
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Definition
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Term
True or false:
Cortical lesions that cause visual disturbances with no other cognitive effects suggest occipital location. |
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Definition
True
occipital lobe is pretty much entirely vision, so a visual disturbance with no other effects is usually in occipital lobe |
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Term
| Explain the classic pupillary constrictor reflex arc. |
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Definition
| Light goes to pretectum: pretectal olivary nucleus (PON) --> bilaterally innervates Edinger-Westphal nucleus-->ciliary ganglion -->iris constrictor muscles |
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Term
| What is it called when there is a preservation of very limited ability to perform visually guided tasks after destruction of the retina to LGN to cortex pathway, in the apparent absence of conscious perception. |
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Definition
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Term
| When you take the LGN-cortical system out, are you (partially or completely) blind? |
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Definition
completely
(LGN cortical system supports conscious system!! Other systems don’t directly engage your conscious visual system) |
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Term
| Where are the 3 places where a lesion would lead to complete loss of conscious vision in specific parts of the visual field form one or both eyes? |
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Definition
| retina/LGN/primary visual cortex (V1) |
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Term
| Lesioning in _______ visual cortex can cause more subtle defects in the ability of a person to understand what they are looking at, but often with normal visual fields and acuity. |
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Definition
extrastriate (away from primary)
ex: may not be able to see moving objects but can see still objects |
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Term
| The LGN is part of the __________. |
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Definition
| thalamus (part of the diencephalon) |
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Term
| The __________ contains sensory relay nuclei for all the senses: sometimes called “the gateway to the cortex”. |
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Definition
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Term
True or false:
LGN is sometimes referred to as LGNv |
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Definition
False
LGNd - no such thing as LGNv |
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Term
If there is a lesion in the right optic tract, which of the following defects will you get?
blindness in the right eye
bitemporal hemianopia
left homonymous hemianopia
right homonymous hemianopia |
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Definition
left homonymous hemianopia - same lesion to half of the eye
(any lesion after chasm will affect vision in both eyes equally to the opposite side) |
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Term
If you have a lesion in the optic radiation of the right primary visual cortex, which of the following will you have?
blindness in the right eye
bitemporal hemianopia
left homonymous hemianopia
right homonymous hemianopia |
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Definition
left homonymous hemianopia
optic radiation is after optic chiasm so same as lesion in the optic tract |
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Term
If you have a right retinal lesion (in the optic nerve), which of the following defects will you get?
blindness in the right eye
bitemporal hemianopia
left homonymous hemianopia
right homonymous hemianopia |
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Definition
blindness in the right eye
(before the optic chiasm) |
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Term
If a person has had surgery in the right temporal lobe, what type of visual defect would you expect them to have?
Blindness in the right eye
Blindness in the left eye
Bitemporal hemianopia
Left Homonymous Hemianopia
Left superior Quandrantanopia
Right superior Quandrantonopia |
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Definition
left superior quandrantanopia
(damages Meyer's loop that is only the superior visual field fiber, is post-chiasmatic so affects both eyes the same, and affects the opposite visual field of lesion) |
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Term
If there is a lesion in the fibers that cross to both eyes due to a pituitary tumor, what would you expect to get?
blindness in the right eye
bitemporal hemianopia
left homonymous hemianopia
right homonymous hemianopia |
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Definition
| bitemporal hemianopia (lose left field on left eye, right field on right eye) |
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Term
a patient presents w/ a left homonymous hemianopia. Of the following choices, where would you expect the lesion to be?
Left retina
Left occipital lobe
Right retina
Right occipital lobe |
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Definition
right occipital lobe
homonymous= post-chiasm
post-chiasm= opposite side |
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Term
True or False:
Chiasm crosses fibers from up and down. |
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Definition
False
Chiasm crosses fibers from left and right, no crossing up/down. |
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Term
Is the monocular crescent located superficially, midway, or deep in the calcarine sulcus?
Is the periphery located superficially, midway, or deep in the calcarine sulcus?
Is the fovea superficially, midway, or deep in the calcarine sulcus? |
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Definition
monocular crescent- deep
periphery- midway
fovea-superficial |
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Term
| Will the superior visual field be above or below the calcarin sulcus? |
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Definition
below
(inferior visual field is above) |
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Term
Migraine visual aura is thought to be due to spreading disturbance on the surface of the ___________ cortex.
What is the visual field property? |
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Definition
primary visual cortex
homonymous (same in both eyes because it's POST-CHIASMATIC!) |
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Term
| The Parvocellular System: Originates with the _____ ganglion cells in the retina, connects to parvo cells in LGN |
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Definition
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Term
| Magnocellular System: originates with the ______ ganglion cells in the retina, connects to magno cells in LGN |
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Definition
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Term
Parvocellular or Magnocellular system?
most strongly associated with extrastriate visual areas in the inferior temporal lobe |
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Definition
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Term
Parvocellular or Magnocellular system?
more strongly associated with extrastriate visual areas in the posterior parietal lobe |
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Definition
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Term
Parvocellular or Magnocellular system?
Neurons respond well to color and fine detail, not so strongly to rapid motion or low contrast |
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Definition
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Term
Parvocellular or Magnocellular system?
Neurons respond well to rapid motion and low contrasts, not so well to color or fine detail. |
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Definition
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Term
| The primary visual cortex has how many layers? Which ones belong to the magnocellular pathway and which ones belong to parvocellular pathway? |
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Definition
6
1-2 Magnocellular (ventral LGN layers)
3-6 Parvocellular (dorsal LGN layers)
-NOT related to dorsal and ventral pathways! |
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Term
| Do the 6 cell layers of the primary visual cortex get input from 1 eye or both eyes? |
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Definition
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Term
| *Which cell layer on the primary visual cortex receives CONTRALATERAL input? |
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Definition
| 1,4,6 (cross the river styx) |
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Term
| *Which cell layer on the primary visual cortex receives IPSILATERAL input? |
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Definition
| 2.3.5 (stay on the same side) |
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Term
Which LGN neuron projects (i.e. send axons) to the cortex?
Which LGN neuron makes only local connections? |
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Definition
relay neurons (relay the same signal from the retinal ganglion cells that contact them)
interneurons |
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Term
| Are there more or less interneurons than relay neuron? |
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Definition
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Term
| n primates (nearly) all visual information that gets to cortex must first go through the __________. |
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Definition
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Term
| What are the other synonyms for the primary visual cortex? |
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Definition
Area V1 (visual first area)
Brodmann’s area 17
Striate cortex - heavy band of myelinated axons in layer 4 (stria of Gennari) |
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Term
| The LGN to V1 pathway is known as the _________ or ___________ pathway for vision. |
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Definition
| The LGN to V1 pathway is known as the thalamocortical or geniculostriate pathway for vision. |
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Term
| Neurons in ____ are *selective for oriented lines/angles and essential for conscious vision. |
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Definition
V1 (region of cerebral cortex)
Not something you see in retina or LGN. |
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Term
True or false:
Extrastriate visual cortex is much larger than striate cortex. It is a very strict and simple hierarchy. |
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Definition
True to first statement.
False to second. (not a simple hierarchy, very complicated) |
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Term
True or False:
A large fraction of the brain is visual. Thus, damage to the brain quite often causes problems with vision. |
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Definition
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Term
| Lesions in the retina/LGN/V1 cause effectively (partial or complete) blindness in specific regions of the visual field (depending on where the lesion is) |
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Definition
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Term
True or false:
As you get farther away from V1, lesions can cause more abstract defects in vision |
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Definition
True
vision is about ANALYZING an image. If the information gets into the brain but the systems that analyze it for some aspect are damaged, then you will have a deficit in that aspect of perception but possibly no defects in gross visual fields or acuity |
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Term
(Dorsal or Ventral) cortical pathway is concerned with "What" stream of visual processing.
Is this mainly dominated by (magno or parvo) input? |
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Definition
Ventral
parvo (color and fine detail) |
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Term
(Dorsal or Ventral) cortical pathway is concerned with "Where" stream of visual processing.
Is this mainly dominated by (magno or parvo) input? |
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Definition
Dorsal
magno (speed and motion) |
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Term
| Where would you expect the lesion to be in a patient with prosopagnosia (otherwise normal vision but can’t tell faces apart) with no corresponding loss of acuity or visual fields? |
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Definition
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Term
| What are the small, but important part of the dorsal stream that respond well to MOTION/perception of motion? |
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Definition
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Term
| If a patient has trouble with motion perception, where would you expect the lesion to be? |
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Definition
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