Inferior Colliculus & Medial Geniculate Body

Question 1

What is the major nucleus between the SOC and IC? Is it obligatory? What nucleus is it physiologically similar to?

Answer 1

Nucleus of lateral lemniscus, similar to the IC,

Not obligatory because all paths do not go through there.

Question 2

What is the purpose of ICC?

Answer 2

ICC (central nucleus)-part of core ascending aud pathway that receives excitatory and inhibitory primary input, care a lot about responding to frequency

Question 3

What is the purpose of ICX?

Answer 3

ICX (external nucleus) plays role in multisensory integration

Question 4

What is the purpose of ICD?

Answer 4

ICD (dorsal cortex)- receives descending inputs from aud cortex and projects in ICC (plays a role in the efferent system)

Question 5

Explain the tonotopicity of the IC.

Answer 5

Iso-frequency sheets

Low frequency - dorsal
High frequency - ventromedially

Question 6

List three stimulus properties that we start to get tuning to at the level of the IC.

Answer 6

Sound duration, amplitude modulation, frequency modulation

Question 7

What is the limit of phase locking in the IC?

Answer 7

Up to 600 Hz

Question 8

What are the three main sections of the MGB?

Answer 8

Medial, ventral, dorsal.

Question 9

Which section of the MGB is the main auditory relay?

Answer 9

Ventral

Question 10

What is the limit of phase locking in the MGB?

Answer 10

Only 10% can phase lock up to 1000 Hz, most up to 250 Hz

Question 11

Outputs from MGB project where?

Answer 11

Project to the auditory cortex