Audition

Question 1

Amplitude

Answer 1

Intensity of sound (LOUD)

Question 2

Frequency

Answer 2

Number of compressions per second (hz) pitch is related to freuqncey

Question 3

Sound travels in ear

Answer 3

Sound wave-> eardrum-> ossicles(hammer,anvil, stirrup)-> oval window

Question 4

Corti composed of …

Answer 4

Basilar membrane

Tectorial membrane

Question 5

Basilar membrane

Answer 5

Auditory receptors, hair cells are mounted here.

Question 6

Tectorial membrane

Answer 6

Rests on hair cells

Question 7

Mechanism of sound detection

Answer 7

1. Tympanic membrane activates ossicles
2. stirrup makes oval window vibrate setting in motion all the fluid in the cochlea
3. Basilar membrane containing organ of corti pulsates moving hair cells
4. Hair cell is sheared by tectorial membrane
5. Opening ion channels in membrane of neuron and signal travels down axon

Question 8

Frequency mechanism 1

Answer 8

Low frequencies up to 100 hz

Basilar membrane vibrates in synchrony with the sound wave producing 1 action potential per wave

Number of neurons activated determines intensity

Question 9

Frequency mechanism 2 (volley method)

Answer 9

> 100 hz

A neuron phase locked to the parks of sound waves

Each sound wave produces a volley of impulses he various fibers

Up to 5000

Question 10

Place mechanism

Answer 10

> 5000 hz

Cochlea base basilar membrane is narrow and stiff

Cochlea apex basilar membrane is wider and not as stiff

Vibration strikes basilar membrane and sets up a traveling wave

Max displacement at particular place along the basilar

Traveling wave for low frequency vibration peaks at or near apex

Higher frequencies, point max displacement is closer to base

Question 11

Axons of each auditory nerve synapse in the…

Answer 11

Ipsilateral cochlear nuclei

Question 12

From ipsilateral cochlear nuclei…

Answer 12

Many projects lead to superior olives on both sides of brain stem

Question 13

From superior olives…

Answer 13

Axons project via lateral lemniscus to the inferior colliculi (tectum)

Question 14

From inferior colliculi…

Answer 14

Axons then project to medial geniculate nuclei of thalamus

Question 15

From thalamic neurons…

Answer 15

Project to primary auditory cortex

Question 16

Lateral and maedial superior olives react to differences in what heard…

Answer 16

Medial: arrival time differences

Lateral: amplitude differences

Question 17

Both lateral and medial project to…

Answer 17

Inferior colliculus :

Deep layers of inferior colliculus are lid out according to auditory space. Allowing location of sound sources in the world. The shallow layers are laid out retinoptopically

Question 18

Auditory cortex located in

Answer 18

Temporal lobe

Question 19

Core region or auditory cortex

Answer 19

Includes primary cortex

Question 20

Belt of auditory cortex

Answer 20

Surrounds core region

Question 21

Secondary cortex outside belt

Answer 21

Referred to as a parabelt areas

Question 22

How many separate areas of secondary auditory cortex are thee in primates

Answer 22

10

Question 23

A1 neurons

Answer 23

Sound frequency

Damage does not produce deafness

Impaired at defying a sequence of sounds (melody)

Question 24

A2 (secondary auditory cortex) neurons

Answer 24

Best to complex combo of sounds

Question 25

Two streams of auditory cortex

Answer 25

Anterior auditory pathway Posterior auditory pathway

Question 26

Auditory signals to two areas of association cortex

Answer 26

Prefrontal cortex Prosterior partietal cortex

Question 27

Anterior auditory pathway

Answer 27

Involved in identifying sounds (what)

Question 28

Posterior auditory pathway

Answer 28

Involved in locating sounds (where)

Question 29

Lesions of auditory cortex

Answer 29

Results in few permanent hearing deficits Hinders sound localization and pitch discrimination

Question 30

Total deafness..

Answer 30

Rare because multiple pathways 2 kinds: Conductive deafness: damage to ossicles Nerve deafness: damage to cochlea