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Neuroscience Week 2 > Central Vision Processing I > Flashcards

Central Vision Processing I Flashcards

1
Q

vision

A
  • we’re so good at it we take it for granted
  • eye is a tiny part of what happens
  • not a webcam, it has evolved
  • computational task that’s different from who’s integrating it
  • high order processing needs integration and analysis
  • receptive field gets larger from retina to temporal cortex
  • not a measurement of physical properties, takes in the whole picture
  • Lady Gaga
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2
Q

coming from the retina

A
  • visual information transduced, processed, and represented:
  • faithful spatial representation of visual space/position-retinotopy and receptive field
  • intensity, luminance-photons absorbed/transduced by photo-pigments, rods vs cones
  • differential spectral absorption- 3 cone types for color
  • spatial contrast-center-surround receptive fields, edge detection
  • on vs off, positive and negative contrast, sign of contrast, luminance increments and decrements
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3
Q

visual pathways

A
  • retina to LGN to occipital lobe
  • nasal retinal fibers with temporal information cross at the chiasm
  • left side of visual field to right side of both eyes and then right side of brain (temporal don’t cross, nasal do)
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4
Q

order of layers in the occipital lobe

A

-contra ipsi ipsi contra ipsi contra

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5
Q

neurons

A
  • optic tract/ radiations neurons still only have information from 1 eye
  • doesn’t collaborate until striate cortex
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6
Q

macular sparing

A

-because 50% of cortex devoted to that small part of the retina

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7
Q

occipital lobe

A

-fibers from thalamus form layer 4 called the stria

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8
Q

meyers loop

A
  • optic radiation fibers in the temporal lobe (carrying superior visual field and inferior retina information)
  • easily damaged
  • neurons go synapse on the inferior bank
  • parietal radiations are carrying inferior visual field and synapse on the superior bank
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9
Q

perisol cells

A
  • part of the magnocellular (M) pathway

- bigger pathway and more ventral

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10
Q

midget cells

A
  • highest acuity

- part of the parvocellular (P) pathway-which is more dorsal

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11
Q

K pathway

A
  • koneo
  • fills in spaces between P and M
  • color
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12
Q

P pathway

A

color,
low luminence contrast,
higher spatial acuity (midget cells),
lower temporal resolution (motion is in M pathway)

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13
Q

M pathway

A
  • perisol cells
  • no color
  • higher luminance contrast
  • lower spatial acuity
  • higher temporal resolution
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14
Q

common properties of receptive fields in the retina and LGN

A
  • center surround organization
  • mix of cells with on and off center
  • retinotopically ordered
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15
Q

LGN cell receptive field

A
  • center surround
  • on or off center
  • retinotopically specific
  • monocular- ipsi or contralaterally driven
  • P,M, or K
  • maybe color opponent (red/green or blue/yellow)
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16
Q

LGN inputs

A
  • enter V1 and terminate in layer 4
  • they make ocular dominance columns
  • slab of cells with functionally related areas
  • homology to monkeys
17
Q

neocortex

A
  • has highly conserved laminar architecture with a canonical pattern of wiring of inputs and outputs which cascade from lower to higher cortical areas
  • circuitry is the computation
18
Q

receptive fields of the retina and LGN

A
  • center surround
  • off vs on
  • on is white on grey
  • off is black on grey
19
Q

orientation tuning

A
  • neurons are orientated to a certain angle and fire more APs at that angle
  • neuron still has other receptive field properties, this is just a new one
  • this is so we can see the outline of shapes/objects
20
Q

hubel/wisel serial model for orientation tuning

A
  • each second order neuron has input from many LGN neurons

- LGN neurons line up and second neuron gets stim in orientation from their on centers and likes that angle

21
Q

order of receptive fields

A
  • retina-V1-V2-V4-temporal

- add more interpretation each time

22
Q

2 visual processes

A
  • one to extract contours–called form vision

- one to fill in surfaces- color vision

23
Q

color vision

A
  • red green and blue yellow (red plus green)
  • opponent mechanisms
  • only see red when you don’t see green
24
Q

type II color opponent cell- R+ G-

A
  • on with red
  • inhibited with green
  • responds well to red and poorly to green, yellow, and white
  • because white and yellow both have green in them
25
Q

type I color cells

A
  • spatial opponency

- weak color bias

26
Q

type II

A
  • chromatic no spatial

- only center part- red on green off

27
Q

double opponent

A
  • center is one thing and surround is opposite

- chromatic and spatial

28
Q

cortical columns

A
  • ocular dominance
  • orientation
  • zebra stripes for orientation
29
Q

vertical vs oblique electrode

A
  • vertical shows all same orientation
  • oblique shows succession of orientations
  • cortical circuitry runs vertically across layers
30
Q

CO blobs

A
  • color tuned
  • fill in the space between ocular dominance columns and orientation columns
  • retinotopy is also a map
  • makes manyyyy big maps so we can see the world better
31
Q

visual coverage

A
  • one square of the cortex has all the possibilities because it has all the columns
  • 2 mm of cortical territory has complete set of columns
32
Q

extrastriate cortex

A

split into thick, pale, thin segments

  • thick for motion
  • pale for form
  • thin for color
  • lead into this pattern from V1 adds another layer of complexity
  • takes what you interpreted from V1 and overlays the layers onto it
33
Q

visual heirarchy

A
  • complicated

- parietal or temporal pathway

34
Q

parietal

A

where

  • bilateral lesion leads to deficit in discrimination of landmarks
  • draw half the picture
35
Q

temporal

A

what

  • object discrimination
  • bilateral lesions of the temporal lobe leads to a behavior deficit in a task that requires discrimination of objects

Neuroscience Week 2 (6 decks)

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