Chap 13

Question 1

What are the interactive functions of areas V1 to V5 ?

Answer 1

V1: Line orientation
V2: Form
V3: Dynamic form
V4: Color
V5: Motion

Question 2

What are the 3 principles of the Wiring Diagram of the visual cortex?

Answer 2

1. V1 is the first processing level, projects to all other occipital regions
2. V2 is the second level, that can also project to other regions
3. After V2, 3 pathways emerge to the parietal cortex and inferior temporal cortex

Question 3

Where do the 3 streams from the occipital lobe project to ?

Answer 3

1. Dorsal to the parietal cortex
2. Ventral to the temporal cortex
3. STS stream to the temporal cortex

Question 4

What are some distinct functions of the 2 main pathways ?

Answer 4

Parietal
- object/facial/body analysis
- analysis of landmarks and biological motion
Temporal
- voluntary eye movement
- directed grasping and reaching
- visuomotor guidance

Question 5

What are the 5 main Visual functions ?

Answer 5

1. Vision for action
2. Action for vision
3. Visual recognition
4. Visual space
5. Visual Attention

Question 6

Describe vision for action and action for vision

Answer 6

Vision for action
- visual processing to perform directed movements (ex reaching for a cup)
Action for vision
- distinguishing between stimuli for selective processing

Question 7

Describe visual recognition, space and attention

Answer 7

Recognition
- identifying objects, foods, people
Space
- knowledge of objects relative to ourself and to other objects
Attention
- neurons response selectively to different stimuli at a given place and time to make specific movement

Question 8

What are the 3 arguments suggesting the dorsal stream has visual control of actions ?

Answer 8

1. neurons in the posterior parietal region are only active when the brain acts on visual information
2. Must act as a connection between visual world and action taken on it
3. lesions to the parietal cortex cause deficit to visual motor spatial control

Question 9

What do imaging studies suggest about facial and spatial recognition ?

Answer 9

1. the temporal lobe lights up when asked to identify faces
2. the parietal lobe lights up when asked to locate a dot that was placed somewhere on a face

Question 10

What is apperceptive agnosia ?

Answer 10

Failure to recognize objects
- caused by damage to the lateral parts of the occipital lobes

Question 11

What is associative agnosia ?

Answer 11

Failure to recognize objects despite its apparent perception
- cant match shapes, but can draw them from memory
- caused by damage to the anterior temporal lobe

Question 12

What is prosopagnosia ?

Answer 12

Failure to recognize faces including one’s own
- caused by damage right below the calcarine fissure

Question 13

If blindness occurs in both visual fields, where is damage most likely ?

Answer 13

The eye, the retina or the optic nerve

Question 14

What is monocular blindness ?

Answer 14

• damage to the eye, retina or nerve produces blindness in the specific eye

Question 15

What is bitemporal hemianopia ?

Answer 15

• blindness in both temporal (outside) fields
• caused by disturbance to the chiasm

Question 16

What is nasal hemianopia?

Answer 16

• blindess in one nasal field (half of one visual field)
• caused my lateral chiasm lesions

Question 17

What is homonymous hemianopia ?

Answer 17

• blindness in one entire visual field (half of each visual field/each eye)
• caused by damage to the optic tract, geniculate body or V1

Question 18

What are scotomas ?

Answer 18

lesions that cause blindspots

Question 19

What is cortical Blindness ?

Answer 19

When a person has no conscious ability to see due to damage, but can report on the shape of the an object presented to them in the “blind” field

Question 20

What is the outcome of V4 damage ? Referring to the JI case study

Answer 20

lost the ability to see color, and after time also lost the ability to remember, think or dream in color
- there is a link between imagery and memory that is dependent on certain cortical structures

Question 21

What is the outcome of V5 damage ? referring to the case study ?

Answer 21

Patient could not see liquid filling a cup or people entering and leaving rooms, they simply appeared

Question 22

What is optic ataxia ?

Answer 22

deficit in visually guided hand movements like reaching and grasping

Question 23

What is the outcome of damage to the right and left occipitotemporal region ?

Answer 23

• damage to the right= deficit in face identification
• damage to the left= deficit in reading