Chapter Four

Question 1

What is spatial organization?

Answer 1

How the environmental stimulus is processed in specific locations

Spatical = location- left, right, up, down
Image of stimulus - represented spatially in the striate cortex through electrical signals

Question 2

What is retinotopic Map?

Answer 2

Image from retina can be electronically mapped out in the striate cortex (V1)

Electronic map = a map of electrical signals going to certain locations of the brain

Question 3

What is Cortical Magnification?

Answer 3

How the small fovea accounts for a large area in the striate cortex (V1) (location of what you are focusing on is large/magnified

Question 4

Electrical signals from the fovea account for how many percent on the striate cortex (V1)?

Answer 4

Fovea = makes up only 0.01% of the retina

HOWEVER, 8-10% of the electronic map in V1 comes from the Fovea

Question 5

What is brain imagining?

Answer 5

Methods to examine the electronic map of the V1 and see brain activities

Question 6

What is the difference between positron emission tomography (PET) and functional magnetic resonance imagine (fMRI)?

Answer 6

Positron Emission Tomography (PET) - injecting low dose of radioactive chemical in bloodstream to see blood flow in the brain
-more brain activity = more blood flow

Functional Magnetic Resonance Imagining (fMRI) -rely on magnetic properties, not on radiative chemical. (similar to PET but more precise)

Hemoglobin - carries oxygen in blood

• contains iron - can be used for magnetic info
• more brain activity = more hemoglobin in blood

Question 7

Columns

Answer 7

Columns = a group of neurons firing in a specific area of the striate cortex
- processing receptive fields from the retina

Question 8

Location columns

Answer 8

Location columns = Receptive fields in retina are same location as cortex

Question 9

Orientation columns

Answer 9

Orientation columns (direction/ position) = neural firing in a column of the cortex occurs when stimulus is positioned in a particular direction

Question 10

Hyper Columns

Answer 10

Hyper Columns (more) = a location column with all orientations of a stimulus

Question 11

In examining a stimulus, what property should we know about the perceptual system in the striate cortex?

Answer 11

Cortical Property

• image of stimulus does not have to resemble (look the same way) in the visual cortex
• neurons in visual cortex just need electrical info to represent stimulus

Question 12

In examining a scene, what is tiling?

Answer 12

Tiling - location columns working together to cover entire receptive fields
- looks like placing bathroom tiles

Question 13

Know the streams or pathways for recognizing what, where, and how for an object in the brain.

Answer 13

Streams - (what, where, how) pathways leading to other brain areas

Question 14

What Pathway

Answer 14

WHAT -also known as ventral pathway or stream

• ventral = lower part of the brain
• striate cortex to TEMPORAL LOBE (what) = ID OBJECTS
• Responsible for identifying objects

Question 15

Where Pathway

Answer 15

WHERE - also known as dorsal pathway or stream

• dorsal = upper part of the brain
• striate cortex to PARIETAL LOBE (where) = LOCATION of objects
• Responsible for location of objects

Question 16

How Pathway

Answer 16

HOW - also known as action pathway

• located in dorsal stream for where pathway (parietal lobe)
• deals with taking action (what you do to an object)

Question 17

Ablation definition

Answer 17

lesioning/ cutting part of the brain

Question 18

Object discrimination definition

Answer 18

Object discrimination is picking the correct shape; lesioning temporal lobe (what pathway)

Question 19

Landmark discrimination problem

Answer 19

Monkeys were required to respond to a previously indicated location. (evidence for the dorsal, or where, visual processing stream)

Question 20

Ventral Pathway

Answer 20

WHAT pathway

Question 21

Dorsal Pathway

Answer 21

WHERE pathway

Question 22

Double Dissociation

Answer 22

Identifying how between what/where processes

Question 23

Who was Patient D.F? What visual problem did he have?

Answer 23

Trouble with WHAT(ventral) but not HOW(dorsal) (p. 85-86)

-Mail slot experiment-

Question 24

Size Illusion Experiment (Ganel and coworkers)

Answer 24

People without brain damage where asked to detect line difference

• Length estimation task: focus on ventural (what) pathway - perception is not accurate
• falsely assume line 1 is smaller than line 2
• Grasping task: focusing on dorsal (how-action) - perception is accurate
• fingers detect line 1 as longer than line 2

Question 25

What is a module?

Answer 25

Modules- BRAIN AREAS containing neurons that specialize in processing certain information

Question 26

Fusiform Face Area (FFA)

Answer 26

Models in the temporal lobe

FFA = Faces

Question 27

Parahippocampal Place Area (PPA)

Answer 27

Models in the temporal lobe

PPA = Locations

Question 28

Extrastraite Body Area (EBA)

Answer 28

Models in the temporal lobe

EBA = Bodies (not faces)

Question 29

What did Gauthier and coworkers find in the Grebes experiment? How does experience play a role in neural processing> What is the expertise hypothesis?

Answer 29

Greebles Experiment
• What is the experiment about?
- To demonstrate expertise effect using fMRI to determine level of activity in Fusiform Face Area (FFA) in response to faces & “Greebles”
• What were the results?
- FFA neurons responded poorly to the Greebles but well to the faces
- After trained in “Greeble recognition”, participants were able to rapidly identify many different Greebles by name
- After training, FFA neurons responded as well to Greebles as to faces
- FFA area of cortex responds not just to faces, but to other complex objects too; objects that neurons respond to can be established by experience with those objects
• Expertise hypothesis
- the idea that human proficiency in perceiving certain things can be explained by changes in the brain caused by long exposure, practice, or training