SOC

Question 1

What does the MSO do? What are the main inputs? What type of cell is it (EE, EI, EO, etc)?

Answer 1

• ITD
• Direct, bilateral excitatory inputs from spherical bushy cells
• Indirect, bilateral inhibitory inputs from globular bushy cells
• Most are EE: neurons excited from both ears

Question 2

What does the LSO do? What are the main inputs? What type of cell is it (EE, EI, EO, etc)?

Answer 2

• ILD
• Direct, ipsilateral excitatory inputs from spherical bushy cells
• Indirect, contralateral inhibitory inputs from globular bushy cells
• Most EI: neurons excited by ipsi, inhibited by contra
• Some EO: neurons excited by ipsi, no reaction to contralateral

Question 3

Explain the tonotopic organization of the MSO.

Answer 3

-Over representation of low frequencies

Question 4

Explain the tonotopic organization of the LSO.

Answer 4

-Over representation of high frequencies

Question 5

Are MSO neurons tuned to ITD or IPD? Why?

Answer 5

• ITD
• Best delay is independent of frequency
• There is an ITD that the neuron loves to fire at

Question 6

Rank order the following in terms of firing rate at relatively large levels for an MSO neuron: ipsilateral, contralateral, bilateral.

Answer 6

-Bilateral, contralateral, ipsilateral

Question 7

Draw firing rate as a function of ITD for the MSO.

Answer 7

• Y axis: number of spikes

- X axis: ITD (I leads –> C leads)

Question 8

Draw firing rate as a function of ILD for the LSO.

Answer 8

• Y axis: number of spikes

- X axis: ILD (I>C –> C<i></i>