Lecture 44 - Vision Flashcards

1
Q

Vision

A

A dynamic, interactive process of motor and sensory function mediated by the eyes for the purpose of simultaneous organization of posture, movement, spatial orientation, manipulation of the environment and to its highest degree perception and thought

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2
Q

What are the 3 optical components of the eye

A
  1. Cornea
  2. Lens
  3. Iris
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3
Q

The cornea and the lens

A

Refract light to focus image on the retina

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4
Q

Iris

A

Controls the amount of light that enters the eye

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5
Q

The 2 neural components of the eye are the

A
  1. Retina
  2. Optic Nerve
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6
Q

Fovea

A

Sharpest central vision and contains only cones

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7
Q

Optic disc

A

The blind spot of the eye where no photoreceptors are (where optic nerve is)

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8
Q

The 2 photoreceptors of the eye are

A
  1. Rods
  2. Cones
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9
Q

Rods

A

Night vision and dim light and low resolution and converge onto single ganglion cell

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10
Q

Cones

A

Bright light and provide color and high resolution detail

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11
Q

What are the 3 types of cones

A
  1. Red
  2. Green
  3. Blue
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12
Q

Color blindness

A

When a person lacks a certain type of cones

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13
Q

What are the visual pigments in rods and cones

A

Rods: Rhodopsin
Cones: Iodopsin

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14
Q

T or F: The eye has both monocular and binocular visual field

A

T

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15
Q

eye teaming

A

It is binocular vision -> ability to use info from both sides at once

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16
Q

Binocular vision is important for

A

depth perception (stereopsis)

17
Q

What disorders can impair binocular vision

A

Cranial nerve palsy, eye injury, cataracts, strabismus (abnormal eye alignment)

18
Q

Describe the pathway of the visual field back to the cortex

A
19
Q

Describe retinotopy and somatotopy (vision)

A

Areas of left and right visual field are represented in specific areas on the retina which align with the somatotopy of the visual cortex

20
Q

T or F: Visual pathway do stop at the primary visual cortex

A

F, they dont

21
Q

T or F: The left visual hemifield is picked up by left nasal retina and right temporal retina

A

T

22
Q

Visual Processing

A

Accurate input of visual info and integration of sensory and proprioceptive info that influences and guides motor output

23
Q

Visual acuity

A

How clearly we see things

24
Q

Focal/Parvocellular Vision

A

Detailed (What is it)

25
Q

Spatial/Magnocellular Vision

A

Big picture (Where is it)

26
Q

Focal System 5 Characteristics

A
  1. What is tested during eye exam
  2. Detailed
  3. Colour vision
  4. Sensitive to high contrast (detailed stimuli)
  5. Transmits more slowly
27
Q

Spatial System 5 characteristics

A
  1. Responds rapidly
  2. Sensitive to large contours, lower contrast stimuli
  3. Not good for detail
  4. More distributed in periphery of retina
  5. Large impact on balance/posture and function
28
Q

T or F: We need to be able to switch back and forth between the focal and spatial system

A

T

29
Q

What can affect the switch back between focal and spatial system and symptoms

A
  1. Neurological events -> stroke, concussion
  2. Lesions

Symptoms: Headaches, blurred vision, memory and balance impairments

30
Q

Bimodal processing occurs in the

A

Ventral and dorsal streams

31
Q

Dorsal Stream

A

Primary visual cortex along posterior parietal lobe (Spatial system: Where is it?)

32
Q

Ventral Stream

A

Primary visual cortex along posterior temporal lobe (Focal system: What is it?)

33
Q

What are 3 common lesions that affect dorsal stream and describe them

A
  1. Visual neglect: Inattention to stimuli in visual field opposite to side of lesion
  2. Optic Ataxia: Poor accuracy with visual guided movement
  3. Motion Blindness: Can see objects at rest, but not when object is moving
34
Q

What are 3 common lesions that affect ventral stream and describe them

A
  1. Prosopagnosia: Cannot recognize people’s faces
  2. Object agnosia: Cannot recognize object
  3. Cortical Colour Blindness: Cannot recognize colour