Chap 17

Question 1

What are the 3 types of neural fiber pathways ?

Answer 1

1. Association pathways
2. Projection pathways
3. Commisural pathways

Question 2

Describe the first type of neural fibre pathway

Answer 2

• long fibre that connect distant neocortical areas
• short fibre connecting adjacent areas

Question 3

Describe the 2nd type of neural fibre pathway

Answer 3

• Ascending fibre from lower brain areas (ex. from the thalamus)
  Descending fibers to the brainstem

Question 4

Describe the 3rd type of neural fibre pathway

Answer 4

Connect the two hemispheres (primarily the corpus callous)

Question 5

Describe Leipmann’s theory of apraxia

Answer 5

Verbal command to move the left hand is processed in the left hemisphere before going to the right side to produce movement
- with disconnection the left side cannot inform the right side to move the left hand

Question 6

What is Downers Experiment ?

Answer 6

disconnection in monkeys causing disconnection syndromes

Question 7

What are the main results of Downers experiment ?

Answer 7

• left amygdala removed, visual information is unavailable to the motor system
• the right amygdala intact, left-eye is covered, but the right side circuit for species-typical behavior is intact

Question 8

What is colossal Agenesis ?

Answer 8

• patients born without a corpus callosum
• have lower IQ, impaired language abilities, visual spatial and reasoning deficits, memory deficits and motor ability deficits

Question 9

How does disconnection affect olfaction ?

Answer 9

system is NOT crossed
- will not be able to name odors from the right nostril since speech is on the left
- could pick out an object matching the smell

Question 10

How does disconnection affect vision ?

Answer 10

• cannot read or answer questions about visual info from the left visual field since their is disconnection from the left side speech zones

Question 11

How does disconnection affect auditory information ?

Answer 11

In the dichotic listening task left ear input is suppressed
- no input from the left ear is reported, though we would expect some direct access from left ear to left speaking side, but with disconnection this direct access does not appear

Question 12

What are hubs ? rich hubs ?

Answer 12

Connect modules to one another
- with more connections the hubs becomes ‘rich’

Question 13

How are hubs involved in neurodegeneration ?

Answer 13

neurodegenerative disorders start in one module and slowly proceed along rich-hub connections to other modules