The hearing brain Flashcards
define sound
the mechanical pressure wave in a medium such as air or water
the three parts of the ear
1- outer ear
2- middle ear
3- inner ear
Outer ear
- pinna funnels sound into auditory canal
Middle ear
amplifies sound - mallecus - incus - stapes mechanically amplifying the sound
Inner ear
codes frequency and amplitude
- cochlea: vestibular canal, tympanic canal, cochlear/partition/duct
What is frequency coding
- cochlear vaires in width and elasticity
- different frequencies cause basilar membrane to vibrate differently
- high frequency sounds peak near the oval window
- low frequency sounds peak away from the oval window
what is amplitude coding
- sounds of high and low ampliude are coded differently
- high amplitude sounds will not only activate receptors tuned in their frequency but also suboptimally tuned ones
- thus the number of receptors that fire give some indiacation of the amplitude of the sound
what is transduction and when does it occur
- with no sound, tip link caps hair cells and prevents potassium ions from entering
- resting level -60mV
noise displaces hairs and lets ions in - active level -40mV
What are the brain networks involved in audition
1- auditory nerve
2- cochlear nucleas and inferior colliculus
3- medical geniculate nucleas
4- auditory cortices
what are the issues with localising sounds
From head…
- distance
- elevation
- azimuth (horizontal)
Azimuth
- sound heard in one ear first and then the second ear
What is speech perception
- speech perception involves translating vibrations into meaningful words
what complicates speech perception
- rapid nature of speech
- vibrations of phonemes
- wide variety of potential words to consider
- the need to seperate speech sounds from other nosie
what factors influnce how speech is understood
1- variation of pitch and tone of the speaker
2- stoppy pronunciation
3- co-articulation
phonemic restoration effect
- conextual cues actually cause listeners to fill in phonemes that werent there
visual cues in speech perception
- lip reading
two theories to speech perception
1- special mechanism approach
2- general mechanism approach
special mechanism approach
decoding of speech is done by special purpose mechanism
- phoneme perception exhibits categorical perception
general mechanism approach
speech perception is highly practised task performed by the same mechanisms that decode other sounds
- other types of auditory stimuli show catergorical perception
- ERP recordings similar in music and speech production
- influnce of vision on speech perception
