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Flashcards in 2. Hearing Deck (40)
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1
Q

Nature of sound:

sound caused by…

That are characterised by…

simplest sound wave is…

A

air pressure waves

amplitude (dB) - loudness
Frequency (Hz) - pitch
Phase - position within a cycle

a pure tone - sine wave

2
Q

Nature of sound:

sound caused by…

That are characterised by…

simplest sound wave is…

A

air pressure waves

amplitude (dB) - loudness
Frequency (Hz) - pitch
Phase - position within a cycle

a pure tone - sine wave

3
Q

human hearing range is …

A

20-20,000 Hx

4
Q

Typical vocal range…

A

80-1100Hx

5
Q

Nature of sound:

complec sounds can be built up from…

A

a series of sine waves with varying amplitudes, frequency and phase

can be decomposed into components by Fourier analysis

6
Q

Nature of sound:

what is the fundamental?
What are complex sounds made up of?

A

fundamental = lowest frequency component of a complex sound

many complex sounds are made up of harmonics, - integer multiples of the fundamental

7
Q

Basic physiology of the ear

components of the OUTER EAR

A

Pinna

  • increases the sound amplitude
  • Helps determine the direction from which a sound is coming form

External auditory canal

  • provides protection
  • increases the sound amplitude

Eardrum (tympanic membrane)
- vibrates in response to sound waves
Moves bones in the middle ear

8
Q

Basic physiology of the ear

Components of the MIDDLE EAR

A

ossicles

  • Malleus
  • Incus
  • Stapes

smallest bones of human body

ossicles transmit the vibrations of the eardrum in to the cochlea through lever actions

They also provide protection against high amplitude sounds
- muscles attached to the ossicles restrict the bones’ movements

9
Q

Basic physiology of the ear

components of the INNER EAR

A

semicircular canals
- important for vestibular sense (sense of orientation)

Cochlea
- contains auditory sensory receptors

10
Q

Basic physiology of the ear

The cochlea

  • oval window
A

The cochlear is filled with a watery liquid that moves in response to the vibrations coming from the middle ear

oval window

  • membrane covering opening in the cochlea
  • the stapes is attached directly to oval window (where the vibrations get into the cochlea
  • much smaller than eardrum - size difference further helps amplify sounds waves
11
Q

Basic physiology of the ear

The cochlea canals

A

three canals of the cochlear

  • vestibular canal
  • tympanic canal
  • cochlear duct

separated by

  • Reissner’s membrane
  • basilar membrane (on which hair/auditory receptor cells located in cochlear duct)
12
Q

Basic physiology of the ear

The cochlea canal and membrane orientation/order

A
vestibular canal
> Reissner's membrane 
>> cochlear duct 
>>> Basilar membrane
>>>>Tympanic membrane
13
Q

Basic physiology of the ear

vibrations to neural signals. HOW?

A

the three membranes vibrate in response to vibrations of the oval window

Wen the basilar membrane vibrates, hair cells are also set in motion

converts the vibrations in to neural signals

14
Q

the auditory cortex

What auditory tasks can be performed without the auditory cortex present?

A
  • onset of sound
  • changes in sound intensity
  • Changes in sound frequency
15
Q

Typical vocal range…

A

80-1100Hx

16
Q

Nature of sound:

complec sounds can be built up from…

A

a series of sine waves with varying amplitudes, frequency and phase

can be decomposed into components by Fourier analysis

17
Q

Nature of sound:

what is the fundamental?
What are complex sounds made up of?

A

fundamental = lowest frequency component of a complex sound

many complex sounds are made up of harmonics, - integer multiples of the fundamental

18
Q

Basic physiology of the ear

components of the OUTER EAR

A

Pinna

  • increases the sound amplitude
  • Helps determine the direction from which a sound is coming form

External auditory canal

  • provides protection
  • increases the sound amplitude

Eardrum (tympanic membrane)
- vibrates in response to sound waves
Moves bones in the middle ear

19
Q

Basic physiology of the ear

Components of the MIDDLE EAR

A

ossicles

  • Malleus
  • Incus
  • Stapes

smallest bones of human body

ossicles transmit the vibrations of the eardrum in to the cochlea through lever actions

They also provide protection against high amplitude sounds
- muscles attached to the ossicles restrict the bones’ movements

20
Q

Basic physiology of the ear

components of the INNER EAR

A

semicircular canals
- important for vestibular sense (sense of orientation)

Cochlea
- contains auditory sensory receptors

21
Q

Basic physiology of the ear

The cochlea

  • oval window
A

The cochlear is filled with a watery liquid that moves in response to the vibrations coming from the middle ear

oval window

  • membrane covering opening in the cochlea
  • the stapes is attached directly to oval window (where the vibrations get into the cochlea
  • much smaller than eardrum - size difference further helps amplify sounds waves
22
Q

Basic physiology of the ear

The cochlea canals

A

three canals of the cochlear

  • vestibular canal
  • tympanic canal
  • cochlear duct

separated by

  • Reissner’s membrane
  • basilar membrane (on which hair/auditory receptor cells located in cochlear duct)
23
Q

Basic physiology of the ear

The cochlea canal and membrane orientation/order

A
vestibular canal
> Reissner's membrane 
>> cochlear duct 
>>> Basilar membrane
>>>>Tympanic membrane
24
Q

Basic physiology of the ear

vibrations to neural signals. HOW?

A

the three membranes vibrate in response to vibrations of the oval window

Wen the basilar membrane vibrates, hair cells are also set in motion

converts the vibrations in to neural signals

25
Q

Central auditory pathways

nerve fibres from each cochlear synapse in a number of sites on the way to the primary cortex

the pathway is…

A
The cochlear
> The cochlear nucleus
>> The superior olivary nucleus
>>> The inferior colliculus 
>>>> The medial geniculate nucleus 

NOTE: signal at cochlear nucleus splits and goes to each of the superior olivary nuclei
> beyond this point, input from both ears is present in both hemispheres

26
Q

auditory space perception

basilar membrane does not directly indicate sound locations so

How is auditory space percived?

A

it is a biaural process

  • interaural time different
    »onset difference
    » phase difference
  • interaural intensity difference
27
Q

the auditory cortex

comparing auditory jask abilities with and without the cortex,

What can be concluded

A

the cortex deals with more complex auditory tasks while the lower structures deal with simple aspects of sound

speech perception requires structures beyond the primary auditory cortex

28
Q

theories of encoding

how do auditory system isolate and identify the frequencies of sounds.

HOW?

A

basilar membrane is 30mm long with varying stiffness and widths along its length.

Traveling waves move along the basilar membrane and peak at different points depending on the frequency of the sound

Thus the location of the peak identifies the frequency of the sound

stimulating auditory nerves at different cochlear locations leads to perception of sound in different pitch

29
Q

theories of encoding

Who suffers from frequency specific hearing loss?

A

people who have damage to specific parts of the cochlea

30
Q

theories of encoding

what are tonotopic maps?

A

maps present in the auditory system

depict how auditory neurons are arranged in an orderly manner

31
Q

pitch perception

monoaural encoding refers to…

A

how sound frequency is encoded in each ear

i.e. cochlear nucleus pathway

32
Q

pitch perception

biaural pitch encoding refers to…

A

how structures beyond the cochlear nucleus should be contributing to pitch perception

missing fundamental can be perceived when harmonics are presented in one ear

and can also be receive when presented in different jars

33
Q

Loudness perception

what are the basic mechanisms of loudness perception

A

overall firing rate

range of firing

34
Q

Loudness perception

what factors affect loudness perception

A

sound duration -
longer=louder

frequency

35
Q

Loudness perception

how does frequency effect loudness

A

generally higher frequencies are perceived to be louder

as amplitude increases the effect of frequency becomes smaller

36
Q

auditory space perception

in auditory space perception, you try to determine a sound’s…

A

horizontal direction (azimuth)

vertical direction

distance

37
Q

auditory space perception

describe interaural time diference

A

unless a sound is directly in front or behind, it reaches two ears at different times (onset difference)

> detected by a simple “delay line” mechanisms in brain

same sound will most likely be in two different phases when it reaches each ear (Phase difference)

> but the phase difference is less useful for localising high-frequency sounds

38
Q

auditory space perception

describe inter aural intensity diference

A

the same sound should be a bit more intense at the eat that is closer to the sound source

> the energy of a sound decreases as it travels farther

> the head works as a barrier that reduces the intensity of the sound (sound shadow)
> this effect is more pronounced for high frequency sounds

39
Q

auditory space perception

How does frequency effect auditory space perception

A

interaural time difference (phase) is useful for localising low frequency sounds

interaural intensity difference is useful for localising high frequency sounds

40
Q

auditory space perception

How is head movement useful for auditory localisation

A

by changing the position of the ears you can experience changes in interaural time/intensity differences