Lec 7 Hearing Brain 2

Question 1

nature of sound

Answer 1

sound as outcome of physical movement, changes in air pressure

Question 2

role of outer ear

Answer 2

amplifies frequencies, key in locating sounds

Question 3

role of middle ear

Answer 3

converts airborne vibrations into liquid-borne vibrations

Question 4

role of inner ear

Answer 4

converts liquid-borne sounds into neural impulses

Question 5

what is tonotopic organisation

Answer 5

different regions in the brain area process different frequencies

Question 6

Explain the ‘what’ pathway

Answer 6

Ventral route, found in temporal lobe, semantic content coded hear, also responsible for identifiyng ‘who’

Question 7

Explain the ‘where’ pathway

Answer 7

Dorsal route, found in parietal lobe, codes where sound is coming from , also responsible for the ‘how’

Question 8

define amplitude

Answer 8

loudness- high/low- the energy in a sound wave

Question 9

define pitch

Answer 9

frequency in a sound wave

Question 10

what is inter-aural differences

Answer 10

Difference in time taken for sound to reach one ear, dependent on position of sound source relative to head position.
Youmay hear a sound first/more intensely informing direction/location of sound source

Question 11

head-related transfer function

Answer 11

Brain accounts for and corrects for the distortion of sound created due to head and outer ear (pinna) that are in the way of travelling sound

Question 12

auditory stream segregation

Answer 12

complex auditory scenes (loud party/gig) can be divided into different processing streams for pitch, melody, location in space

Question 13

Cocktail party problem (fMRI study)- method

Answer 13

p’s asked to attend to one of 3 people ina group i.e. low/middle pitched speakers

Question 14

Cocktail party problem (fMRI study)- what 4 brain regions activated? what does each activatr?

Answer 14

IFG (inferior frontal gyrus) activation from pitch cues

Dorsal precentral sulcus (DPresCS) and superior parietal lobule (SPL) activation for location, IPS too

Question 15

what can a spectogram show

Answer 15

physically depict speech as cmplex sound waves (darker areas are vowel- since they have a higher frequency

Question 16

What features are used to produce the sound in our voices

Answer 16

Larynx and articulators

Question 17

In a voice processing study, what happens in silent/passive conditions in the brain

Answer 17

Compared with silent c, bilateral activation in voice-selective regions of human auditory cortex

Question 18

What does the adaptation paradigm show in a voice processing study

Answer 18

(listening to spoken syllables)
voice-selective area (right anterior superior temporal sulcus) sensitive to to change in speaker identity but NOT lexical-phonetic change
= voice processing NOT specific to humans- monkeys do it too

Question 19

TMS effect on voice processing

Answer 19

TMS over the voice-selective area of brain disrupts the ability for voice detection. NOT for loudness judgement of same stimuli

Question 20

What is the problem for Pure Word Deafness patients ?

Cause by what?

Answer 20

NOT actually dea, but cannot identify speech. Perceive speech as distorted, people sound too fast.
Causedby bilateral STG damage (Superior Temporal gyrus)

Question 21

what is speech perception

Answer 21

set of operations transforming auditory signal into mental representations

Question 22

Explain motor theory of speech perception

Answer 22

We perceive spoken words by reproducing a speaker’s movement in our vocal tract as opposed to identifying the sound patterns the speech generated by the speaker

Question 23

What does the strong version of motor theory suggest?

Answer 23

the motor system for speech production is NECESSARY for speech perception

Question 24

Name of key brain area associated with speech production

Answer 24

Broca’s area

Question 25

Support for the Motor Theory

Answer 25

1) McGurk Effect (integration of visual info into what we hear)
2) Categorical speech perception- means we cant perceive sounds we cant produce

Question 26

Neuroscientific evidence for motor theory

Answer 26

motor system is used in speech perception in a process of auditory-to-articulatory mapping

Question 27

What is the opposing caveat to the supporting evidence for motor theory

Answer 27

If motor system is critical for perception of speech sound, then damage to motor speech production system should have substantial impact on ability to perceive speech.
(this is not always the case)

Question 28

Evidence against the strong version of motor theory

Answer 28

From aphasic patients-
Hickok et al- Broca’s aphasia are non-fluent in speech production BUT when given speech perception tasks they perform well, suggesting motor speech system NOT necessary for speech perception

Question 29

D’Ausilio et al’s virtual lesion study as more evidence against strong version of motor theory

Answer 29

The virtual lesions disrupted recognition of phonemes (labial/dental) after TMS applied but ONLY when presented in background noise

Question 30

What does D’Ausilio’s virtual lesion study suggest about the PMC and speech perception

Answer 30

That the PMC (premotor cortex) only contributes to speech perception when the auditory signal is hard to disambiguate

Question 31

Opposing evidence to McGurk effect

Answer 31

When TMS applied over superior temporal sulcus (STS) McGurk effect is disrupted

Question 32

What has categorical speech perception study on phonemic discrimination taks suggested

Answer 32

Not just the motor cortex that processes speech categorically but whole network of brain areas
Conclude that there are multiple routes to speech perception, inc. WHAT (ventral) and HOW (dorsal) routes

Question 33

Which of the two routes are more agreed on in research

Answer 33

the WHAT (ventral) path for semantics is more agreed on in research.
The HOW (where, dorsal) route less agreed on- rather favoured by strong version of motor theory