L7 hearing things Flashcards by Stephanie Cheng

What is the sound/signal emitted by an object/system when hit ?

Impulse response

How well did you know this?

Not at all

Perfectly

What is the fundamental ingredient of complex sounds?

Sine wave

How well did you know this?

Not at all

Perfectly

What is the rate mass-spring systems like to vibrate at?

A rate proportional to the square root of their ‘stiffness’ and inversely proportional to their weight

How well did you know this?

Not at all

Perfectly

In resonant cavities, what will happen to the ‘lumps of air’ at the entrance/exit of the cavity?

It will oscillate under the elastic forces exercised by the air inside the cavity

How well did you know this?

Not at all

Perfectly

What is the preferred resonance frequency?

Inversely proportional to the square root of the volume

How well did you know this?

Not at all

Perfectly

What is the relationship between resonators and sounds?

Positively related, e.g. larger resonators, deeper sounds

How well did you know this?

Not at all

Perfectly

What kind of physical properties are reflected in the frequency spectra they emit when they make sounds?

Size, mass and stiffness

How well did you know this?

Not at all

Perfectly

What is the job of ears?

Perform a time-frequency analysis of incoming sounds

How well did you know this?

Not at all

Perfectly

What is the characteristics of basilar membrane?

Stiff at the base, floppy at the apex

How well did you know this?

Not at all

Perfectly

How will vibrations travel?

From the stapes to the round window and either take a short route through stiff membrane or a longer route through more inert fluid

How well did you know this?

Not at all

Perfectly

Describe the routes (inertia, stiffness)

Shorter route: lower inertia, higher stiffness

Longer routes: Higher inertia, lower stiffness

How well did you know this?

Not at all

Perfectly

Characteristics of helicotrema

No resistance from basilar membrane

How well did you know this?

Not at all

Perfectly

Higher sound frequency will go to which place in the basilar membrane?

Nearer to the base

How well did you know this?

Not at all

Perfectly

What will outer hair cells fire?

Resting potential (X action potential)

How well did you know this?

Not at all

Perfectly

Describe the axons sent to the brain by outer hair cells.

Not myelinated and in small numbers

How well did you know this?

Not at all

Perfectly

Why do outer hair cells jiggle?

To amplify the vibrations by dancing along to the sound

How well did you know this?

Not at all

Perfectly

Advantages of jiggling outer hair cells.

Easier for encoding and picking up by inner hair cells

How well did you know this?

Not at all

Perfectly

Where do hair cells locate?

Organ of Corti

How well did you know this?

Not at all

Perfectly

What do hair cells transduce?

Mechanical vibration of the basilar membrane into electrical signals

How well did you know this?

Not at all

Perfectly

Where do inner hair cells transmit the signals to?

Auditory nerve fibres

How well did you know this?

Not at all

Perfectly

What are outer hair cells?

Mechanical feedback devices which amplify the signal on a tuneable manner

How well did you know this?

Not at all

Perfectly

When hearing researchers talk about sound frequencies, what do they refer ‘event rates’ to?

Fourier (sine wave) components

How well did you know this?

Not at all

Perfectly

Waves have several frequencies according to? (one of each Fourier component sine wave that has non-zero amplitude)

Fourier spectra

How well did you know this?

Not at all

Perfectly

What can the frequency filtering by the basilar membrane can do, to some extent? (Fourier analysis)

‘Decompose’ complex sounds into its constituent frequency components

How well did you know this?

Not at all

Perfectly

What will happen if a complex sound had many frequency components?

The spatial resolution of this 'place code for frequency' becomes quickly overwhelmed

Definition of "Harmonics"

The frequency components are all integer multiples of a lowest, common 'fundamental' frequency

What do physical objects tend to have, what would that lead to?

Modes of vibration leads to sounds with many frequency components, 'overtones' (harmonics)

Describe noise-like sounds

Irregular, non-periodic sounds, no harmonic structure

What are human speech comprise of?

Both periodic (voiced) and non-periodic, noise-like (unvoiced) speech sounds

What does the Fourier Transform encourage us to think of a click?

An infinite series of sine waves, which have started at the beginning of time, continue until the end of time, and all happen to pile up at the one moment when the click occurs

How a click train is perceived when frequencies up to ca 30-50 Hz?

Isolated event

How a click train is perceived when frequencies above ca 30-50 Hz?

Individual clicks combine, and perceive as a continuous hum with a strong pitch

Articulators' movement will ?

Change resonance properties of the vocal tract

What do formants do?

Encode frequencies on broad scale

What do harmonics do?

In fine scale, know which pitch they are ranging (voice tones)

It is whose job to produce a spectrogram of the incoming sound?

Ear

It is whose job to interpret the spectrogram to identify sounds?

Brain

What do auditory nerve discharge rates depend on?

The amount of sound energy near the neuron's characteristic frequency

What is tonotopy?

A place coding for frequency because of basilar membrane tuning

What is phase locking?

The discharge of cochlear nerve fibres to low-frequency sounds occur at particular times

What do phase locking do?

Encodes information about the temporal structure of sounds that is used for hearing of pitch and spatial hearing

What is the auditory pathway?

Nuclei in the brainstem (cochlear and superior olivary nuclei) and midbrain (lateral lemniscus and inferior colliculus) then thalamus

Describe the tonotopy in the cochlear nucleus

The base of the basilar membrane projects to the medial cochlear nucleus, the apex to lateral cochlear nucleus

What is the relationship between iterated rippled noise and periodicity?

Increasing the number of iterations can make iterated rippled noise more periodic, vice versa.

What is the relationship between signal periodicity and pitch?

The less periodic the signal, the weaker the pitch

Neurons in the midbrain or above show much less_________ to amplitude modulated signals than neurons in the _____

phase locking; brainstem

Periodicity maps in midbrain: transition from a _____ to a ___ code

timing; rate

Some neurons have _______ and exhibits _______ (____)

bandpass MTFs; best modulation frequencies; BMFs

Topographic maps of BMF may exist within _______ of the inferior colliculus, "periodotopy"

isofrequency laminae

Baumann et al described periodotopic maps in monkey IC obtained with fMRI. They used stimuli from _____Hz (____) to _____Hz (_____). Their sample size is quite ____. The observed orientation of their periodic map (______) appears to differ from (_____)

0.5; infra-pitch; 512; mid-range pitch; small; medio-dorsal to latero-ventral for high to low; predimonantly caudal to rostral

In marmoset, pitch sensitive neurons are most commonly found on the boundary between ____ and ____

A1; R

What sounds are periodic?

Pitchy sounds

Pitchy sounds means they have many _____ frequency components

harmonic

Missing fundamental stimuli show that there is no straight-forward relationship between _________ and ________.

tonotopy; perceived pitch

_______ of periodicity is important

Temporal encoding

What should we be skeptical of?

The notion of pitch neurons in the brain

Interaural time difference cues are powerful cues to _______, but they are ______ (____)

sound source direction; ambiguous; cones of confusion

Interaural level cues are_________, unlike ITDs

highly frequency dependent

At _____ sound frequencies ILDs tend to become _____, more____, and hence more ________

higher; larger; complex; informative

What is the cue that even people with one deaf ear can also have?

Spectral (Monaural) cues

Spectral (Monaural) cues can tell sounds coming from _______ to ______

top; bottom

'Type IV' neurons in the ______ often have _____ frequency response areas with ______ sidebands. This makes them sensitive to '________' like those seen in ________.

dorsal cochlear nucleus; inhibitory; excitatory; spectral notches; spectral localisation cues

Some reports suggest that anterior cortical belt areas may more selective for _____ and less for _____, while _______ are more location specific.

sound identity; sound source location; caudal belt areas

It has been hypothesized that anterior cortical belt& caudal belt areas may be the starting positions for a ventral 'what' stream heading for ______ and a dorsal 'where' stream which heads for ____

inferotemporal cortex; postero-parietal cortex

Deactivating some cortical areas (A1, PAF) by ____, impairs ______ but impairing others (AAF) does not

cooling; sound localization

Our brain processes binaural (ITD and ILD) and spectral cues to determine _______

sound source direction

The brain's ____ sensitivity is remarkably precise, down to ____ of microseconds

ITD; tens

The _______ are brainstem nuclei where binaural information about ILDs and ITDs respectively is _____ computed

lateral and medial superior olive; first

Higher up in the brain, information from different cues and pathways in ____. Except for the ______, there is no '______' in the _______ brain

combined; superior colliculus; map of auditory space; mammalian

The degree to which different cortical areas specialize in ______ is controversial

spatial hearing

Speech sounds are created when vibrating _______ or _____ or ______ of the vocal tract excite '_____' resonances in cavities in our vocal tracts

vocal folds; temporary; partial obstructions; formant

Change in vocal fold vibration _______ -> pitch change, important for ____, ____, voice tone in tonal languages. Pitch not important in semantics in _______ languages

frequency; melody; prosody; Indo-European

Change in ______ (formants) through '_____' is responsible for most of the _______ in speech. (Dynamics also play a role, e.g. 'voice onset time'

resonances; articulation; semantic category distinctions

Brain transforms ____ to ____ to _____ information as information travels from _____ to _________ and on to many other brain regions

acoustic; phonemic; semantic; primary auditory cortex; superior temporal gyrus

Primary cortex is on _____

Heschel's Gyrus

Human superior temporal gyrus is sensitive to _______ such as 'manner of articulation'

phonetic feature

Mitchell et al argued that words which have similar meanings according to a statistical semantic analysis should produce_______ in those parts of the brain involved in ________.

similar brain activations; interpreting meaning

Mitchell et al built a predictive model which was able to predict evoked brain activity over large parts of the brain, including ____ and _____ lobes, fusiform and _________, medial frontal gyrus and anterior cingulate.

bilateral occipital; parietal; middle frontal gyri