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Opt 662 Midterm II
Dr Kundart
100
Medical
Graduate
11/17/2011

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Cards

Term
What is the wavelength of invariant blue?
Definition
478 nm
Term
What is the wavelength of invariant green?
Definition
503 nm
Term
What is the red wavelength used in the anomoloscope?
Definition
670 nm
Term
What is the wavelength of invariant yellow?
Definition
578 nm
Term
What is the kelvin value of Illuminant A?
Definition
2800 K
Term
What is the kelvin value of Illuminant B?
Definition
4800 K
Term
What is the kelvin value of Illuminant C?
Definition
6800 K
Term
Kollner rule blue-yellow deficits come from damage to what locations?
Definition
Outer retinal structures

Media of the eye
Term
Kollner rule red-green deficits come from damage to what locations?
Definition
Inner retinal structures

optic nerve and pathways
Term
What conditions can cause blue-yellow deficits?
Definition
Nuclear sclerosis (media)

diabetic retinopathy

macular degeneration
Term
What conditions can cause red-green deficits?
Definition
Toxic amblyopia

Leber's optic atrophy

Pathway lesions
Term
What part of vision procesing is V1 responsible for?
Definition
Dominance slabs

Edge detectors
Term
What part of vision procesing is V3 responsible for?
Definition
Local motion

Phi-phenomenon
Term
What is the last cortical area where parvo, konio and magno streams are seen together?
Definition
V3
Term
What part of vision processing is the V4 responsible for?
Definition
color vision

faces

luster


rivalry
Term
Where does the parvocellular stream end?
Definition
V4
Term
What part of vision processing is the V5 resonsible for?
Definition
global motion

complex cells
Term
What is the standing potential for EOG, ERG and EOP?
Definition
EOG = 6.0mV

ERG = 0.06 mV

VEP = 5.0 uV
Term
What are the neutral points for the 3 color anomalies?
Definition
Protan = 492 nm

Deutan = 498 nm

Tritan = 569 nm
Term
What are the copunctal points for the 3 color anomalies?
Definition
Protan = 700 nm

Deutan = Extra spectral purple

Tritan = 430 nm
Term
What are the frequencies of best color discrimination according to the 'W' graph?
Definition
495 nm nad 590 nm
Term
Where do magno cellular axons enter the visual cortex?
Definition
Layer IV C Alpha
Term
Where do parvo cellular axons enter the visual cortex?
Definition
Layer IV C Beta and IV a
Term
Per hemisphere, how many fibers go from the visual cortex to the LGN?
Definition
4 million
Term
Where do the outputs from V1 layer VI go?
Definition
LGN
Term
Where do outputs from V1 layer V go?
Definition
Superior Colliculus
Term
Where do outputs from VI layer II and III go?
Definition
Continues the magno (dorsal) and parvo (ventral) stream
Term
Where is the retinotopic map in the visual cortex?
Definition
Area 17 of V1
Term
The fovea represents what percentage of the retina and cortex, respectively?
Definition
0.2% of the retina but 66% of the cortex
Term
Why do blobs stain with Cytochrome oxidase?
Definition
CO stains cells with lots of mitochondria, i.e. cells with high metabolic activity
Term
What are our edge detectors tuned to detect best, second best, and third best?
Definition
horizontal, vertical, and oblique edges
Term
What do simple cortical cells do?
Definition
Edge detection
Term
What do complex cortical cells do?
Definition
Detect unidrectional movement and edges
Term
What is the dominant input to complex cortical cells?
Definition
Magno more than parvo, thus unidirectional movement detection capability
Term
What kind of cells perform stereopsis?
Definition
Binocular cortical cells
Term
Is ocular dominance at the retinal or cortex level?
Definition
Cortex. The dominant eye will pay greater attention to the input from the dominant eye
Term
What two areas show damage in prosopagnosia?
Definition
Fusiform facial area near V4

Inferior Longitudinal Fasciculus
Term
What is Allethesia?
Definition
Improperly referencing where a stimulus came from
Term
What is teleopsia?
Definition
When an object appears farther away than it truly is
Term
What is pelopsia?
Definition
When an object appears closer than it truly is
Term
What is kinetopsia? Where does it originate in the brain?
Definition
Seeing movement when none is present; medial temporal or V5
Term
What is palinopsia?
Definition
Seeing an object when it is no longer there
Term
What is polyopsia?
Definition
Seeing multiples of a single object
Term
Why do dementia and caffeine cause hallucinations?
Definition
Poor perfusion (hypoxia via ischemia)
Term
What type of hallucination is seen while falling asleep?
Definition
hypnagogic
Term
What type of hallucination is seen while waking up?
Definition
hypnopompic
Term
Describe Delta waves
Definition
1-4 hz, found in deep sleep, young children, or those with brain lesions
Term
Describe Theta waves
Definition
4-8 hz, just before falling asleep, dreaming, or drowsy
Term
Describe Alpha waves
Definition
8-12 hz, the 'dial tone' of the brain. Awake, but eyes closed or relaxed
Term
Describe Beta waves
Definition
12-20 hz, alert or REM dreaming

Is rhythmic in pathology or drug use
Term
Describe Gamma waves
Definition
20-80 hz, higher thinking, problem solving, fear
Term
Visual agnosias most commonly affect what visual field and what lobe?
Definition
left visual field and right parietal lobe
Term
Which is faster, the 'What' or 'Where' pathway?
Definition
Where
Term
What pathway carries color, 'What' or 'Where'?
Definition
What
Term
Which pathway has the most detail, 'What' or 'Where'?
Definition
What
Term
Agnosias stem from defects in which pathway: 'What' or 'Where'?
Definition
What
Term
Visual neglect stems from defects in which pathway: 'What' or 'Where'?
Definition
Where
Term
What is Balint syndrome?
Definition
Triad of simultagnosia, oculomotor ataxia, and oculomotor apraxia
Term
What is the relationship between Broca's, Wernicke's and Visual Neglect?
Definition
They are controlateral to one another usually. Speech and speech understanding are normal (left hemisphere), visual system is faulty (right hemisphere)
Term
What is worse, apperceptive or associative agnosias?
Definition
apperceptive
Term
Where do apperceptive agnosias originate?
Definition
right inferior parietal lobe, fed by MCA

Where pathway
Term
Where do associative agnosias originate?
Definition
left occipitotemporal area near Wernicke's


What pathway
Term
V3 is found in what pathway?
Definition
magno or where pathway
Term
Does EOP voltage potential go up in the light or dark?
Definition
Is greater in the light by a factor of 2x as dark current shuts off, retina hyperpolarizes relative to the positive cornea
Term
From the light peak to the dark trough, what is the ratio of the change?
Definition
200% change
Term
After lights are off, how long until the dark trough potential is realized?
Definition
8 minutes
Term
What is a normal Arden ratio?
Definition
180-250%
Term
What is does an Arden ratio of 165-180 mean?
Definition
Sick receptors or RPE
Term
What does an Arden ratio of 300% mean?
Definition
ocular albinism
Term
What is the #1 thing that EOG is used to dx?
Definition
RPE problems
Term
Can EOG be used to dx small areas of retinal inflammation?
Definition
No, ERG is used for that
Term
What does an ERG measure when a photopigment decouples?
Definition
The Early Receptor Potential (ERP)
Term
Where does the A-wave originate?
Definition
negative deflection from PR
Term
Where does the B-wave originate?
Definition
Positive deflection from Mueller/Bipolar cells
Term
Where does C-wave originate?
Definition
May not be present, only seen with long illumination periods. RPE cells
Term
What is Anton syndrome?
Definition
Blindness that the pt is often unaware of
Term
What causes Anton syndrome?
Definition
birth defects

trauma

Creutzfeld-Jakob

Epilepsy meds
Term
What part of the visual cortex is most important for conscious awareness of vision?
Definition
V1
Term
Does the OKN reflex require the visual cortex?
Definition
No, it is processed in the nuclei of the optic tracts
Term
What is contrast sensitivity at age 4?
Definition
4 cpd (20/150)
Term
What is the Stiles Crawford II effect?
Definition
If colors are perceived from off-axis locations, their color will be slightly shifted toward the red and slightly desaturated
Term
What are the 4 types of stereo cells?
Definition
far and near cells (coarse stereo)

Tuned excitatory and tuned inhibitory cells
Term
What do far stereo cells do?
Definition
Fire if the target is beyond our foveal fixation, and inhibit the near cells at the same time
Term
What do near stereo cells do?
Definition
Fire if the target is nearer than our foveal fixation and inhibit far cells at the same time
Term
What do tuned excitatory cells do?
Definition
Fire when a given value of stereo disparity is detected. Makes up 50% of all stereo cells
Term
What do tuned inhibitory cells do?
Definition
Inhibit stereo detectors and makes up 20% of all stereo receptors
Term
What are the 6 parts of the Retino-Tectal pathway?
Definition
Nucleus of the optic tract

Pulvinar

Pre-Tectum

Superior colliculus

Hypothalamus

LGN
Term
What CN's are part of the Nucleus of the Optic Tract (NOT)?
Definition
CN III, IV, VI, VIII
Term
What is the pulvinar?
Definition
Coordinates auditory and visual inputs into a spatial grid, found in the thalamic nucleus

Helps with visually guided movements and motion processing
Term
What does the human pre-tectum do?
Definition
OKN reflex, it is found in the midbrain
Term
What does the Superior colliculus control?
Definition
Reflexive foveations and reflexive saccades
Term
Why is the hypothalamus part of the NOT?
Definition
In order to get inputs for circadian rhythm timing, seasons, breeding?, mood (SAD)
Term
What allows you to habituate to spatial effects of new glasses?
Definition
The vestibulo-ocular reflex found in the NOT
Term
What is found in V1?
Definition
Dominance slabs and Edge detectors

Magno, Parvo, and Konio pathways
Term
What is found in V2?
Definition
Dominance slabs and edge detectors

Magno, Parvo, and Konio pathways
Term
What is found in V3?
Definition
Medial superior temporal lcoation, processes local motion

Magno, parvo, konio are present, but no longer communicating
Term
What is found in V4?
Definition
Inferior temporal. Parvo stream ends here.

Color vision, facial recognition
Term
What is found in V5?
Definition
middle temporal, processes global motion and end of the magno stream
Term
What are blobs for?
Definition
Color vision, receives input from parvocellular cells in layer 4C Beta, outputs to thin stripes in V2
Term
What are interblobs for?
Definition
sense orientation instead of color. Output to pale stripes of area V2
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