Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

control of human movement > hearing > Flashcards

hearing Flashcards

1
Q

what is a sound?

A
  • alternating waveform consisting of compression and rarefaction and separating of air molecules
  • an oscillating object will cause air to become more or less dense
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what equation works out wavelength

A
  • distance between each troph
  • velocity/frequency
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

frequency (pitch)

A
  • hear because your brain can dissociate between different frequencies
  • if not it would be a continuous noise
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define amplitude (decibels)

A
  • generally expressed as a ratio
  • intensity in decibels = intensity unknown sound/intensity of standard x 10log10
  • standard is mean hearing threshold
  • standard mean corresponds to 10 to power of -11 movement in air molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the range of human hearing

A
  • frequency = 20-20000Hz
  • Amplitude = 0-140dB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

do we have lower sensitivity to low frequencies?

A
  • yes
  • sound pressure levels adjusted to A weighting
  • down-scales low frequencies to acknowledge lower sensitivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

presbycusis

A
  • as you get older you lose auditory hair cells
  • influences high frequencies
  • 20 y/o have lower vol of sound to perceive it than older
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

having ability to listen to ten octaves of hearing

A
  • first 2 octaves = low bass 20-80Hz
  • Third and forth = upper bass 80-320Hz
  • fifth-seventh = mid-range 320-2560Hz
  • eighth = upper mid-range 2560-5120Hz
  • ninth-tenth = treble 5120 to 20,000Hz
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

neurons in the ear and its frequencies

A
  • primary afferent neurons coming from cochlea - sends auditory info to brain
  • you can define frequency responsiveness of any neuron in terms of a tuning curve
  • neurone responds preferentially to a frequency
  • neurons respond differently to different frequencies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the basic anatomy of the ear

A
  • three parts
  • outer = air filled, tympanic membrane (eardrum)
  • middle = air filled, ossicles
  • inner = fluid filled, cochlea and vestibular system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how sound moves through ear

A
  1. tympanic membrane deflects
  2. middle ear bones moves and pushes oval window
  3. membrane in oval window moves causes cochlea fluid to move back and forth
  4. basilar membrane moves (contains organ of hearing)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

roles of the ossicles

A
  • middle ear acts as a lever
  • ossicle bones = malleus, incus and stapes
  • convert high amplitude/ low force motion at eardrum into low amplitude/high force motion at oval window
  • called impedance matching
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the stapedius reflex

A
  • 2 muscles act on ossicles
  • contraction of muscles pulls stapes away from oval window
  • decreases transmission of vibrational energy to cochlea
  • stapedius reflex occurs in response to very loud sound
  • occur during speech
  • prevents hearing damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what happens when sound gets to cochlea

A
  • sound vibrated through ears
  • outer chamber of fluid vibrating
  • 3 chambers (scale) vestibule, media, tympani
  • when sound comes in it shifts column of fluid back and forth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

basilar membrane

A
  • organ of corti within it
  • auditory nerve comes out of it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

organ of corti in detail

A
  • does the work
  • 2 rows of hair cells inner and outer
  • vestibular hair cells = physical motion
  • auditory hair cells = physical motion poured by sound
  • embedded in tectorial membrane
  • underneath is the basilar membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what happens in organ of corti when sound reaches it?

A
  • vibration of basilar membrane
  • cause relative motion of tectorial membrane = activates hair cells
18
Q

what type of hair cells do we have?

A
  • one cell = kinocilium
  • rest of the hair cells = stereocilia
  • moving towards little hairs you get inhibition
  • move towards kinocilium you get activation
19
Q

what is pitch place theory?

A
  • when basilar membrane wobbles, different parts of it will be activated at different frequencies
  • closer to oval window = high frequencies
  • other end = low frequencies
20
Q

high frequency sound activates basilar membrane where?

A

proximal end

21
Q

what is Fourier analysis

A
  • the ear is one
  • any waveform can be decomposed into sine waves of various frequencies
22
Q

explain tuning of hearing

A
  • far more sharp by the passive mechanics of basilar membrane alone
  • amplification happening
23
Q

amplification happening

A
  • inner hair cells for sensation
  • outer are for amplification
  • outer contain prestin so whole cell can oscillate
  • they will exaggerate sound through positive feedback cycle (active undamping)
24
Q

can outer hair cells generate sound

A
  • yes
  • otoacoustic emissions are echos in response to clicks delivered to ear
  • ## absense indicates problem of inner ear
25
Q

what is hearing most sensitive for?

A
  • speech
  • 400-3000Hz
26
Q

temporary notch

A
  • damage depends on level and duration
  • anything over 85dB is potentially damaging
  • mild notch at 4kHz
27
Q

what happens to sound once its past as primary afference

A
  • sound activates many areas from cochlear to auditory cortex
  • arrives in brainstem via 3 neurons
  • passes through colliculus and arrives at primary auditory cortex
28
Q

what is the primary auditory cortex

A
  • responsible for your perception of sound
29
Q

what is the superior olive

A
  • in brainstem
  • decifers differences in loudness and timing
30
Q

what is sound localisation?

A
  • distance (range) and bearing (azimuth and elevation)
  • judge distance = high frequencies travel less well (far away is dominated by bass)
  • bass travels best, sibilants worst (relative attentuation)
  • echoes - reverberation
  • judging direction = inter-aural timing/phase differences with left and right ear
  • inter-aural volume differences
  • spectral colouring - loss of high frequencies through head
31
Q

what is the cocktail party effect?

A
  • to understand conversation from an individual speaking amongst many others
  • involves localisation cues and vision
32
Q

what are inter-aural volume differences?

A
  • ILD
  • head provides sound shadow
  • better for high frequencies (whistle nerve right ear it is much louder in right)
  • bass sounds volume in both ears similar
  • vowels emphasised, sibilants attenuated more far away and speech becomes more bass
33
Q

inter-aural time delay

A

-ITD
- click from left will arrive at left ear first then right soon after
- detect ITDs at 10us (1degree)

34
Q

explain the Jeffress theory

A
  • ITD detection
  • involved superior olive
  • neurones in this act as coincidence detectors
  • neuron splits into 5 different pathways when reaching olive (5 left 5 right)
  • action potentials arrive simultaneously from both ears, MSO neurone more likely to fire
  • relies on differing lengths of axons and provides a neuronal map of sound location
35
Q

inter-aural phase differences

A
  • better in low frequencies
  • if sound is a continuous tone, use phase difference to localise
  • not useful when wavelength is shorter than head (high frequency)
  • L-R difference of 360 degree sounds same as 0 degree
36
Q

does your head size matter?

A
  • big heads = large L/R time difference - use timing differences (ITD)
  • small heads = not much L/R time difference - loudness differences (ILD_
  • small heads = better detecting high frequency
37
Q

what is the cone of confusion?

A
  • sounds emanating from different locations can produce identical ILD and ITD profiles at two ears
  • e.g., sounds from behind can sound like the front
  • if you tilt or turn head it alters the cone so a previously ambiguous sound is now localised
38
Q

what does the pinna of your ear do?

A
  • outer ear
  • attenuates sounds from certain directions and amplifies from others
  • invisible to low frequencies (bass)
  • coming from behind it can shield high frequencies more = different spectral content
39
Q

what sounds are easier to localise

A
  • narrow bands of frequencies and gradual onsets and offsets are harder to localise
  • longer, more intense broadband sounds attract attention
40
Q

auditory reaction times

A
  • typically 140-160ms
  • visual reaction time is slower at 180-200ms
  • frequency matters
  • 1kHz = optimal reaction
41
Q

startle responses

A
  • loud sound 120dB
  • evokes blink at 40ms and neck contraction at 80ms
  • mediated by brainstem
  • bypasses cortex via reticular formation 80ms
42
Q

can a startle improve simple reaction time

A
  • yes
  • signal accompanied by loud sound reaction time is faster

control of human movement (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions