Central Pathways

Question 1

Describe the Lemniscal auditory pathway

Answer 1

• ICC/MGB to layer IV of primary auditory cortex
• Sensory
• Tonotopic, temporal structure encoded

Question 2

Describe the non-Lemniscal auditory pathway

Answer 2

ICC/MGB to layer I of associative cortex
Integrative, polysensory
Broad tuning, not tonotopic, rapid habituation

Question 3

Name the 2 developmental gradients in the CANS

Answer 3

Peripheral to Central

Cortical maturation by layers: layer I, then IV-V, later II-III

Question 4

Precocious

Answer 4

Hearing mature at birth

Question 5

Altricious

Answer 5

Born deaf

Question 6

When is myelin density adult-like?

Answer 6

6-12 months of age

Question 7

Neurons are 50-60% of adult size at what age?

Answer 7

Birth

Question 8

What age are neurons adult-like

Answer 8

1 year of age

Question 9

When is myelin density adult-like?

Answer 9

6-12 months of age

Question 10

When is the temporal lobe formed by?

Answer 10

27th fetal wk

Question 11

Does the complexity of neurons increase with age?

Answer 11

Yes

Question 12

Name an intrinsic factor that affects neural connections

Answer 12

Gene expression

Question 13

Name an extrinsic factor that affects neural connections

Answer 13

Sound exposure

Question 14

How does deafness affect the End Bulbs of Held?

Answer 14

Decreased branching

Question 15

How does deafness affect :
the spiral ganglion cells?
Ipsi CN?
Contra preference in auditory cortex?

Answer 15

SGCs: Decreased #
Ipsi CN: Decreased volume
Contra pref: Decreased preference