Ch. 8 - visual object recognition and spatial processing

Question 1

Visual areas

Answer 1

occipital (v1 and v2), parietal, and temporal lobe. two separate processing streams: “what” and “where”.

Question 2

Ungerleider and Mishkin model

Answer 2

There is extensive output from the occipital lobes to other cortical regions that is carried primarily by two major pathways:

• the inferior route (ventral course into the temporal lobes)
• the superior route (dorsal course into posterior regions of the parietal lobe).

Distinguish them according to types of process they mediate
What and where

Question 3

The ventral stream

Answer 3

Specialized for object recognition and perception.

WHAT

temporal lobe

Question 4

The dorsal stream

Answer 4

Specialized in spatial perception

WHERE

parietal lobe

Question 5

DF-patient

Answer 5

Damage to ventrolateral region of occipital lobe because of carbon monoxide poisoning. difficulty recognize and discriminate between simple object, such as different size.

Question 6

Ventral stream and object recognition

Answer 6

Our retina work in 2D, so the brain must reconstruct a third dimension in order for us to see in 3D.

beginning of the stream -> simple stimulus characteristics (width, shading, texture)

Make considerable use of color, which is important for object recognition because it allows us to distinguish between figure/ground.

Question 7

visual agnosia

Answer 7

Dysfunction to the ventral stream. two forms of object recognition failure: apperceptive and associative agnosia

Question 8

Apperceptive agnosia

Answer 8

Associated with CO poisoning.

Unable to identify the object, but can describe its physical features such as its size, color etc.

Severe cases; damage to occipital and surrounding posterior regions is widespread - patient cannot even copy simple shapes, match them or discriminate between them.

Question 9

Associative agnosia

Answer 9

Have a hard time to identify and name specific objects, unable to draw from memory.

Difficulty in linking percept to meaning.

Question 10

Prosapognosia

Answer 10

inability to perceive faces. The degree of impairment is variable.

People often have other abnormalities of object recognition as well, but there is found a double dissociation between object recognition and facial recognition indicating that it is a separate skill.

Question 11

Soldier S (case study)

Answer 11

Suffered from prosapognosia, he was unable to interpret facial expression even though he could see movement of fat that led to chained expression.
Couldn’t even recognize his own face in a mirror.

Question 12

Aquired alexia

Answer 12

Inability to recognize written words after brain injury/damage

Question 13

Prosapognosia and the brain

Answer 13

evidence for a specialized role for the right hemisphere in face recognition.

Damage can be located to occipital and medial temporal regions of the right hemisphere.

Fusiform gyrus.

Question 14

Region involved in route-finding tasks

Answer 14

Hippocampus, also posterior parietal cortex.

Question 15

Test spatial memory

Answer 15

Corsi block test

Question 16

Area in spatial processing

Answer 16

Right hemisphere is predominantly, but left can also be.

Categorical spatial memory = left prefrontal cortex, coordinate spatial memory = right prefrontal cortex.