Lecture 44 - Vision

Question 1

Vision

Answer 1

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

Question 2

What are the 3 optical components of the eye

Answer 2

1. Cornea
2. Lens
3. Iris

Question 3

The cornea and the lens

Answer 3

Refract light to focus image on the retina

Question 4

Iris

Answer 4

Controls the amount of light that enters the eye

Question 5

The 2 neural components of the eye are the

Answer 5

1. Retina
2. Optic Nerve

Question 6

Fovea

Answer 6

Sharpest central vision and contains only cones

Question 7

Optic disc

Answer 7

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

Question 8

The 2 photoreceptors of the eye are

Answer 8

1. Rods
2. Cones

Question 9

Rods

Answer 9

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

Question 10

Cones

Answer 10

Bright light and provide color and high resolution detail

Question 11

What are the 3 types of cones

Answer 11

1. Red
2. Green
3. Blue

Question 12

Color blindness

Answer 12

When a person lacks a certain type of cones

Question 13

What are the visual pigments in rods and cones

Answer 13

Rods: Rhodopsin
Cones: Iodopsin

Question 14

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

Answer 14

T

Question 15

eye teaming

Answer 15

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

Question 16

Binocular vision is important for

Answer 16

depth perception (stereopsis)

Question 17

What disorders can impair binocular vision

Answer 17

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

Question 18

Describe the pathway of the visual field back to the cortex

Answer 18

Question 19

Describe retinotopy and somatotopy (vision)

Answer 19

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

Question 20

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

Answer 20

F, they dont

Question 21

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

Answer 21

T

Question 22

Visual Processing

Answer 22

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

Question 23

Visual acuity

Answer 23

How clearly we see things

Question 24

Focal/Parvocellular Vision

Answer 24

Detailed (What is it)

Question 25

Spatial/Magnocellular Vision

Answer 25

Big picture (Where is it)

Question 26

Focal System 5 Characteristics

Answer 26

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

Question 27

Spatial System 5 characteristics

Answer 27

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

Question 28

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

Answer 28

T

Question 29

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

Answer 29

1. Neurological events -> stroke, concussion 2. Lesions Symptoms: Headaches, blurred vision, memory and balance impairments

Question 30

Bimodal processing occurs in the

Answer 30

Ventral and dorsal streams

Question 31

Dorsal Stream

Answer 31

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

Question 32

Ventral Stream

Answer 32

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

Question 33

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

Answer 33

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

Question 34

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

Answer 34

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