Chapter 6: Object recognition

Question 1

What is object constancy?

Answer 1

The ability to recognize objects in multiple situations

Question 2

What are the two pathways for visual (and auditory) perception and what aspect do they cover?

Answer 2

1) Dorsal: where (superior longitudinal fasciculus): respond to large areas of space
2) Ventral: what (inferior longitudinal fasciculus): respond to specific areas, especially fovea

Question 3

What is the difference between visual agnosia and optic ataxia and which streams have deficits for each case?

Answer 3

Agnosia = not able to recognize objects due to lesion in ventral stream

Optic ataxia = not able to use visual cues to guide actions in space due to lesion in dorsal stream

Question 4

What area in the ventral stream is especially important for object recognition?

Answer 4

LOC: lateral occipital cortex

Question 5

What is cue invariance?

Answer 5

The insensitivity to specific visual cues that define an object (drawing, picture, statue of a dog is always a dog)

Question 6

What causes an increase in bloodflow in the LOC?

Answer 6

Novel and familiar objects. The LOC cares the most about shape, not texture

Question 7

What is repetition suppression (RS)?

Answer 7

The neural response to a stimulus is lower in the second presentation compared to the first. The neural response is more efficient when it’s recently activated

Question 8

What is fNIRS?

Answer 8

Functional near infra-red spectroscopy; method for measuring bloodflow in infants head with an EEG like cap, but an fMRI concept (oxygenated vs. not oxygenated blood)

Question 9

What is multistable perception?

Answer 9

Observer experiences competition in perception. E.g. in binocular rivalry task

Question 10

What are the grandmother cells hypothesis and the ensemble coding hypothesis?

Answer 10

Grandmother cell: states that there is one neuron that fires for for example recognizing your grandmother

Ensemble theory: a set of cells respond to your grandmother. This theory accounts for recognizing novel objects and seeing similarities to familiar things in them

Question 11

What is the difference between a shallow feed forward network and deep feed forward network?

Answer 11

The shallow feed forward network is an artificial network that has no hidden layers and has a clear structure.
The deep feed forward network has multiple hidden layers and reflects for example the visual system

Question 12

What is the difference between decoding and encoding brain signals?

Answer 12

Decoding: predicting the stimulus based on brain activity
Encoding: predicting brain activity based on the stimulus

Question 13

What is the difference between top-down and bottum-up effects?

Answer 13

Top-down: you are searching something, controlled by prefrontal regions
Bottum-up: a stimulus gets your attention

Question 14

What is the function and location of the fusiform face area (FFA)?

Answer 14

Recognizing faces independent of facial expressions. It also responds to other familiar things, but it has a strong bias for faces

Question 15

What is the difference between the activity in de lateral face areas and activity in anterior face area?

Answer 15

Lateral: responds mostly to shape of the face
Anterior: responds mostly to appearance of the face

Question 16

What is the PPA and what is its function?

Answer 16

Parahippocampal place area is responsive when judging spatial properties or relations, such as landscapes

Question 17

What are the EBA and FBA?

Answer 17

Extrastriate body area and fusiform body area are both responsible for making judgments about the body

Question 18

What is the OFA?

Answer 18

Occipital face area responds, just like FFA, to faces

Question 19

What is apperceptive visual agnosia?

Answer 19

The components of an object are perceived, but they can’t be put together to a whole. It’s related to object constancy: you can only recognize it when it includes the important features (seeing stack of lego, but not the building)

Question 20

What is integrative visual agnosia?

Answer 20

Patients don’t see objects holistically. They perceive parts of an object (they see a door, but not a house)

Question 21

What is associative visual agnosia?

Answer 21

Perception without recognition (perception of house and can draw a picture of it, but can’t describe)

Question 22

What are forms of specific agnosia?

Answer 22

A form of agnosia can be worse for certain categories. E.g. selective agnosia for fruit and vegetables

Question 23

When do you use the unusual object test and how does it work?

Answer 23

Use it to examine if you have agnosia. E.g. identification of an object shown from different angles.

If you have damage in posterior regions right hemisphere –> poor performance

If you have left-hemisphere or anterior lesions –> perform fine

Question 24

What are the two theories of object knowledge?

Answer 24

1) Sensory/functional hypothesis
2) Domain-specific hypothesis

Question 25

What is the sensory/functional hypothesis?

Answer 25

Conceptual knowledge is organized around representations of sensory properties (such as shape and color) and motor properties and these representations depend on specific neural systems

E.g. a hammer’s visual representation is associated with shape and motor representations of actions

Question 26

What is the domain-specific hypothesis?

Answer 26

Conceptual knowledge is organized by categories that are evolutionary relevant to survival and reproduction

Dedicated neural systems evolved because they enhanced survival by more efficiently processing categories of objects

Question 27

What is prosopagnosia?

Answer 27

Failure to recognize face, often due to lesions in ventral pathway in FFA or OFA. It’s often bilateral, but otherwise right side

Congenital prosopagnosia: brain activity in FFA remains the same, but structural connections of anterior temporal cortex with the rest of face processing is disturbed

Question 28

What is the relationship between face recognition and autism?

Answer 28

Fewer neurons in fusiform gyrus and less activity, so they are poorer in recognizing faces

Question 29

What are the two types of recognition?

Answer 29

Holistic analysis = seen as a whole, such as face perception

Analysis by parts = parts are combined to a whole, such as reading