Object Recognition 1

Question 1

What is involved in object recognition?

Answer 1

Intact Vision
Ability to perceive shapes, colors, etc.
Discriminate between different objects
Identify what an object is
Recognition (memory)
Naming (language)
Object meaning/function

Question 2

What is visual agnosia?

Answer 2

Unable to recognize object just based on seeing (could name object after touching it)

Question 3

What is agnosia?

Answer 3

Failure of knowing

Question 4

What areas of the brain are important for object recognition?

Answer 4

Ventral and Dorsal Parietal Lobe and Occipital Cortices
- Occipital lobe
- Fusiform gyrus
- Parahippocampal area

Question 5

What are the 2 visual processing streams?

Answer 5

Dorsal Pathway (Where/How)
Ventral Pathway (What)

Question 6

Where are the 2 visual processing streams located?

Answer 6

Where/How pathway (dorsal) is located in the posterior parietal cortex
What pathway (ventral) is located in the inferior temporal cortex

Question 7

What are the 3 pieces of evidence for the 2 visual processing streams?

Answer 7

Monkey lesions
Human lesion patients
Neuroimaging

Question 8

What is the monkey lesion study?

Answer 8

Monkeys completed an object discrimination task and a landmark task. After experienced a brain lesion connected to the 2 pathways the were not successful in the same task but could complete the opposite task.

Question 9

What did the neuroimaging (PET) study find?

Answer 9

Found what brain area show greater activity for…
Object > Position
Position > Object

Question 10

What did examining Patient D.F. lead to?

Answer 10

When there was a lesion to the ventral visual cortex the patient had trouble visually identifying objects but visually-guided action was intact.

Question 11

Where is the object recognition area in the brain?

Answer 11

Lateral Occipital Cortex (LOC)

Question 12

Why is object recognition so hard?

Answer 12

Computational Challenges

Question 13

What are some computational challenges that make object recognition hard?

Answer 13

Visual similarity is not the same as object category
Variability in sensory information
Object invariance

Question 14

What is object constancy?

Answer 14

The ability to recognize objects in countless situations

Question 15

What is object invariance?

Answer 15

Representing objects as the same despite variation in location, size, viewpoint, lighting, etc.

Question 16

What is the evidence for “what” information being processed in the ventral stream?

Answer 16

Patient D.F.
Monkey Lesions
PET and fMRI evidence in humans

Question 17

What is the difference between grandmother cells and ensemble coding?

Answer 17

Grandmother cells: 1 cell is used to encode 1 thing

Ensemble coding: collective coding of multiple collections of neurons

Question 18

What is a downside to grandmother cells?

Answer 18

Not enough neurons for that and if one cell dies then what??