Week 1: Chapter 13 - The Occipital Lobes

Question 1

What is the primary function of the occipital lobe?

Answer 1

It serves as the brain’s main center for vision, shaping perception, guiding movement, and influencing behavior.

Question 2

Where is the occipital lobe located?

Answer 2

At the posterior pole of the cerebral hemispheres, beneath the occipital bone.

Question 3

What structure separates the occipital lobe from the parietal lobe?

Answer 3

The parietal-occipital sulcus.

Question 4

Why is the boundary of the occipital lobe uncertain?

Answer 4

There are no clear landmarks separating it from the temporal and parietal cortices.

Question 5

What is the calcarine sulcus?

Answer 5

A prominent structure housing much of the primary visual cortex (V1) and dividing the upper and lower visual fields.

Question 6

What does the lingual gyrus contain?

Answer 6

Parts of visual areas V2 and VP.

Question 7

What is the role of the fusiform gyrus?

Answer 7

It houses area V4 and is crucial for processing color and complex shapes.

Question 8

What are the three key anatomical features of the visual cortex?

Answer 8

Calcarine sulcus, lingual gyrus, and fusiform gyrus.

Question 9

What was the old model of visual processing?

Answer 9

A strict hierarchical model moving linearly from V1 to V2 to V3.

Question 10

What is the current model of visual processing?

Answer 10

A distributed hierarchical model with parallel and interconnected pathways.

Question 11

What is the function of V1?

Answer 11

Receives input from the LGN and sends projections to all other occipital areas.

Question 12

How is V2 connected in the visual cortex?

Answer 12

It connects to all other occipital regions.

Question 13

What happens after processing in V2?

Answer 13

Three parallel pathways emerge to the parietal cortex, superior temporal sulcus (STS), and inferior temporal cortex.

Question 14

What is the function of the dorsal stream?

Answer 14

It is involved in visually guided movement and projects to the parietal cortex.

Question 15

What is the function of the ventral stream?

Answer 15

It handles object recognition and projects to the inferior temporal and STS pathways.

Question 16

What does the ventral stream process?

Answer 16

Color, faces, and motion perception.

Question 17

Why is the modern visual processing framework considered non-linear?

Answer 17

Because it involves multiple, interactive pathways for complex perception and movement coordination.

Question 18

What visual functions are processed in V1 and V2?

Answer 18

Color, form, and motion.

Question 19

Which area processes color and receives input from V1’s blob areas?

Answer 19

V4.

Question 20

What does V5 (MT) specialize in?

Answer 20

Motion detection.

Question 21

Which area processes dynamic form (shape of moving objects)?

Answer 21

V3.

Question 22

What happens when V4 is damaged?

Answer 22

Complete color blindness, including loss of color imagination and memory.

Question 23

What are the effects of V5 damage?

Answer 23

Inability to perceive motion; objects vanish when moving.

Question 24

What results from V3 damage?

Answer 24

Form perception deficits, though total loss requires V3 and V4 damage.

Question 25

What happens when V1 is damaged?

Answer 25

Cortical blindness, but some unconscious visual processing remains (blindsight).

Question 26

Which area might allow limited visual awareness despite V1 damage?

Answer 26

V3.

Question 27

Which brain lobes are involved in extended visual processing?

Answer 27

Parietal, temporal, and frontal lobes.

Question 28

What is the FFA responsible for?

Answer 28

Face perception.

Question 29

What is the PPA specialized for?

Answer 29

Scene layout and appearance.

Question 30

What does the STSp process?

Answer 30

Moving bodies.

Question 31

What did Andrews et al. (2002) demonstrate about the FFA?

Answer 31

FFA responds more strongly when faces are perceived in ambiguous images like Rubin’s vase.

Question 32

What are LIP and AIP/PRR involved in?

Answer 32

Eye movements and object-directed grasping, respectively.

Question 33

What is vision for action?

Answer 33

Visual guidance for specific movements, like reaching or catching.

Question 34

What is action for vision?

Answer 34

Active visual scanning of relevant features, such as eyes and mouth on a face.

Question 35

What is visual recognition?

Answer 35

Identification and categorization of objects, symbols, and faces.

Question 36

What is visual space?

Answer 36

Organizing visual information into egocentric and allocentric maps.

Question 37

What is visual attention?

Answer 37

Filtering and focusing on relevant stimuli, like text on a page.

Question 38

What is egocentric space?

Answer 38

Object location relative to oneself, used for movement control.

Question 39

What is allocentric space?

Answer 39

Object location relative to other objects, used in spatial memory.

Question 40

What are the two primary visual streams identified by Milner and Goodale?

Answer 40

Dorsal stream for action and ventral stream for object recognition.

Question 41

What did patient studies by Milner and Goodale reveal?

Answer 41

Dorsal damage impairs action, ventral damage impairs recognition.

Question 42

What activates posterior parietal neurons?

Answer 42

Movement toward a visual object.

Question 43

How many visual pathways connect V1 to the parietal cortex?

Answer 43

Three, each coding different movement-related visual aspects.

Question 44

What are symptoms of parietal cortex lesions?

Answer 44

Visuomotor and visuospatial impairments.

Question 45

What is the function of the STS stream?

Answer 45

Integrates visual, auditory, and somatosensory input and processes biological motion.

Question 46

Where does the STS stream originate?

Answer 46

Both parietal and temporal pathways.

Question 47

What did Haxby’s PET studies show about face matching and spatial tasks

Answer 47

Face matching activates the temporal lobe, spatial tasks activate the parietal cortex.

Question 48

Which area is linked to motion detection?

Answer 48

V5.

Question 49

Which areas are activated for shape recognition?

Answer 49

Superior temporal sulcus (STS) and ventral temporal lobe.

Question 50

Which area processes color perception?

Answer 50

V4 in the lingual gyrus.

Question 51

What role does the prefrontal cortex play in visual processing?

Answer 51

It generates top-down predictions to speed up perception.

Question 52

What is an example of top-down visual prediction?

Answer 52

A baseball player anticipating a pitch using experience.

Question 53

Where do top-down predictions originate?

Answer 53

Prefrontal cortex.

Question 54

How do top-down and bottom-up processes interact?

Answer 54

Top-down memory-based predictions combine with real-time sensory input.

Question 55

How does visual information from the retina project to the brain?

Answer 55

Left retina halves project to the right brain, and right retina halves to the left.

Question 56

What indicates damage outside the brain in vision loss?

Answer 56

Visual disturbance in only one eye.

Question 57

What happens with damage to a specific V1 region?

Answer 57

Loss of vision in a specific part of the visual world.

Question 58

What is monocular blindness?

Answer 58

Loss of sight in one eye due to retina or optic nerve damage.

Question 59

What is bitemporal hemianopia?

Answer 59

Loss of both temporal visual fields due to a lesion in the medial optic chiasm.

Question 60

What is nasal hemianopia?

Answer 60

Loss of one nasal visual field from a lateral chiasm lesion.

Question 61

What is homonymous hemianopia?

Answer 61

Blindness in one entire visual field from cuts in the optic tract, LGN, or V1.

Question 62

What is quadrantanopia?

Answer 62

Loss of vision in one-quarter of the visual field.

Question 63

What is macular sparing?

Answer 63

Preservation of central vision due to dual blood supply or bilateral foveal projection.

Question 64

What is a scotoma?

Answer 64

A small blind spot caused by a small occipital lesion, often unnoticed.

Question 65

What symptom did B.K. experience after V1 damage?

Answer 65

A left visual field scotoma with visual noise.

Question 66

What does B.K.'s case suggest?

Answer 66

Visual processing functions like form, color, and motion are independent.

Question 67

What is blindsight?

Answer 67

Unconscious visual processing despite cortical blindness.

Question 68

What was special about G.Y.'s blindsight?

Answer 68

Some conscious awareness of motion with V5 and prefrontal activation.

Question 69

What did J.I. lose after V4 damage?

Answer 69

Color perception, imagination, and memory.

Question 70

What did P.B. retain despite visual impairment?

Answer 70

Conscious color perception, with intact V1 and V2 activation.

Question 71

What condition did L.M. develop after V5 damage?

Answer 71

Akinetopsia — inability to perceive motion.

Question 72

What did D.F.'s form agnosia reveal?

Answer 72

Ventral stream damage impaired recognition, but dorsal stream allowed action.

Question 73

What condition did V.K. develop after parietal damage?

Answer 73

Optic ataxia — impaired visually guided grasping despite object recognition.

Question 74

What does D.'s prosopagnosia suggest about hemispheric asymmetry?

Answer 74

Right occipito-temporal damage impairs face recognition.

Question 75

What did T.'s alexia suggest?

Answer 75

Left occipito-temporal damage affects reading and color naming.

Question 76

What conclusion comes from these case studies?

Answer 76

Visual functions are specialized, and perception is fragmented.

Question 77

What is apperceptive agnosia?

Answer 77

Failure to form coherent percepts despite intact basic vision. They struggle with: - Object recognition - Copying simple figures - Matching simple figures

Question 78

What is a typical symptom of apperceptive agnosia?

Answer 78

Simultagnosia — only one object perceived at a time.

Question 79

What causes apperceptive agnosia?

Answer 79

Bilateral lateral occipital damage, often from carbon monoxide poisoning.

Question 80

What is associative agnosia?

Answer 80

Inability to link visual percepts to stored knowledge.

Question 81

Where is the lesion in associative agnosia?

Answer 81

Higher ventral stream, especially the anterior temporal lobe.

Question 82

What is prosopagnosia?

Answer 82

Inability to recognize familiar faces.

Question 83

Where is prosopagnosia typically localized?

Answer 83

Bilateral fusiform gyrus damage.

Question 84

What is alexia?

Answer 84

Word blindness, or inability to read.

Question 85

Which areas are affected in alexia?

Answer 85

Left fusiform and lingual gyri.

Question 86

What is visuospatial agnosia?

Answer 86

Difficulty navigating environments and recognizing landmarks.

Question 87

Where is visuospatial agnosia localized?

Answer 87

Right medial occipitotemporal region.

Question 88

What do visual agnosias illustrate about perception?

Answer 88

That it's made of distinct, specialized functions in the ventral stream.