Visual System

Question 1

The _____ is the point of fixation that has the highest visual acuity.

Answer 1

fovea (of the retina)

Question 2

The optic nerve is part of _____ nervous system.

Answer 2

CNS

Question 3

Partial crossing of optic nerve axons occurs at the optic _______ prior to forming the optic tracts.

Answer 3

optic chiasm

Question 4

What is the fan of the lateral geniculate nucleus?

Answer 4

relay nucleus of thalamus

Question 5

What are optic radiations?

Answer 5

fibers that arise from lateral geniculate nucleus

Question 6

The visual cortex terminates adjacent to ______.

Answer 6

calcarine fissue

area 17

Question 7

What is Area 17?

Answer 7

primary visual cortex

Question 8

What are Area 18 and 19?

Answer 8

visual association cortex

color, movement, etc

Question 9

Visual perception is processed in the ______ cortex.

Answer 9

occipital

Question 10

After Central processing in the occipital cortex, information can flow via which two streams?

Answer 10

dorsal stream: motor control

ventral stream: conscious awareness of visual experience

Question 11

Dorsal stream to the ______ cortex.

AKA?

Answer 11

posterior parietal cortex

“ambient vision”

Question 12

Ventral stream to the _____ cortex.

AKA?

Answer 12

inferotemporal cortex

“focal vision”

Question 13

The dorsal stream operates on information from:

Answer 13

fovea and retinal periphery

Question 14

Describe dorsal stream qualities:

Answer 14

Can operate in dim light
Info used to guide ACTION
Info about characteristics of object

Question 15

Describe ventral stream qualities:

Answer 15

Requires good lighting
Conscious perceptual experience of vision
Recognition of objects

Question 16

The ventral stream operates on information from:

Answer 16

fovea

Question 17

What is visual agnosia? Which stream?

Answer 17

VENTRAL STREAM LESION:

inability to recognize

Question 18

How does optical ataxia present? Which stream?

Answer 18

DORSAL STREAM LESION:

• inability to reach in the right direction for objects
• inability to adjust grip to shape of object

Question 19

Evidence for two streams is based on:

Answer 19

Perception-Action Dissociations

Question 20

What is optical array?

Answer 20

pattern of light rays entering the eye

Question 21

What info does optical array provide?

Answer 21

relative position of objects and self

Question 22

Changes in optical array are called:

Answer 22

optical flow

Question 23

Where is optical flow processed?

Answer 23

posterior parietal lobe

Question 24

What is optical flow used for?

Answer 24

o Stability and Balance
o Velocity of movement of observer through the environment
o Direction of movement relative to position of fixed objects in environment
o Movement of objects relative to the observer
o Time to Contact between observer and object in the environment

Question 25

______ is a crucial variable that brain uses to calculate motor requirements like catching a ball.

Answer 25

time to contact