Hearing

Question 1

What is Extracellular Microelectrode recording?

Answer 1

Inserting an electrode close to a neuron to measure it’s electric signal

Question 2

Where is the voltage-gated sodium chanel, and what does it do?

Answer 2

• This is in the cell wall of a neuron
• When open it allows sodium ions to move into the neuron

Question 3

What kind of charge do sodium ions have?

Answer 3

A positive charge.

Question 4

What is the resting mV of a neuron? and what does it reach during an action potential?

what is the time course of an action potential

Answer 4

• Resting is -70 mV
• Action potential up to +40 mV
• 0-5 ms time course

Question 5

What is depolarization, repolarization, and refractory period?

Answer 5

• These are periods of an action potential
• Depol: neuron moving from -70 to +40 mV
• Repol: mV dropping again to below -70
• Refractory: returning to baseline

Question 6

What are the perceptual dimensions of amplitude, frequency, and complexity?

Answer 6

Amplitude = loudness
Frequency = Pitch
Complexity = timbre

Question 7

What are the perceptual dimensions of amplitude, frequency, and complexity?

Answer 7

Amplitude = loudness
Frequency = Pitch
Complexity = timbre

Question 8

Name the 5 major components of the middle and inner ear.

Answer 8

Oval window
Round window
Cochlea
Tympanic membrane
Ossicles

Question 9

Where is the basilar membrane found? What does it code for?

Answer 9

The cochlea.
Position along basilar represents frequency.

Question 10

How are sound wave vibrations transformed in the ear?

Answer 10

• They enter the ear which caused the movement of fluid in the cochlea. (vibration to fluid)
• This cochlea fluid is the *basiliar membrane *
• The movement of this fluid causes vibration in the techtorial membrane (fluid back to vibration)

Question 11

What do vibrations in the techtorial membrane affect?

Answer 11

The movement of stereocilia.

Question 12

What happens when a group of Stereocilia swings to the right or the left.

Answer 12

• Left: chanel narrows, decrease mV of haircell
• Right: chanel opens, allows postive ions to enter the hair cell

Positive ions = potassium and calcium

Question 13

What are more important to earing, the inner or outter hair cells? Why.

Answer 13

The inner hair cells.
* Damage to these cells will result in deafness
* One inner hair cell contributes to the output of multiple spiral ganglier cells
* Mutiple outter hair cells contribute to only one spiral ganglier cell

Question 14

How does the Basilar Membrane reflect frequency?

Answer 14

Different sound frequencies correspond to different lengths of the basilar membrane.
High frequency : appears at the base of the membrane
Low frequency : appears at the apex of the membrane

higher Hz = lower frequency

Question 15

What hemisphere processes signals coming into the left ear?

Answer 15

Signals coming into ether ear are processed in both hemispheres

Question 16

What does having a cochlea implant ealier in life help with?

Answer 16

Language comprehension.

Question 17

What is the function of hair cells?

Answer 17

They convert the physical vibration of the basilar membrane to the ganglion cells. Result is relevant action potentials firing

Question 18

What does the ions change during the seterocilia bend do?

Answer 18

Causes a change in their electrical charge. This releases neuro trasmitter to be released which causes bio gangliar cells to generate action potentials

Question 19

What does the pattern of spiral ganglion cells reflect?

Answer 19

The pattern along the basilar membrane which is coded according to frequency and amplitude

Question 20

What is tonotopic?

Answer 20

organization of the auditory system in a way that preserves the frequency or pitch information of sounds from the cochlea to the auditory cortex