3. Auditory Integration Flashcards
What are sounds?
Vibrations of air molecules
Define the parameters of human perception of sound.
20 - 20,000 Hz
Name the perceptual dimension of AMPLITUDE.
Loudness
How is amplitude measured?
Decibels
Name the perceptual dimension of FREQUENCY.
Pitch (Hz)
Name the perceptual dimension of COMPLEXITY.
Timbre
Hertz =
cycles per second
The ear can be categorised into three parts. Name these three parts.
Outer ear
Middle ear
Inner ear
Name components of the OUTER EAR
- helix, antihelix
- scapha
- triangular fossa
- concha
- auricular lobule (earlobe)
- ear canal
Name components of the MIDDLE EAR
- tympanic membrane (eardrum)
- tympanic cavity
- maiieus
- incus
- stapes
Name components of the INNER EAR
- eustachian tube
- cochlea
- cochlear nerve
- vestibular nerve
What is another name for “ear canal”
external acoustic meatus
Describe the organ of the CORTI
• Found within the cochlear conduct
where transduction from mechanical waves to neural signals takes place
• It contains hair cells (inner and outer)
Each hair cell in the CORTI has ________
approx. 100 stereocilia
What elements can be seen when looking at a cross-section of the cochlea.
- scala vestibuli
- scala media
- scale tympani
- spiral ganglion
- basilar membrane
- tectorial membrane
Describe what happens to the membrane potential of a hair cell during a sound-induced vibration.
- excitatory force opens ion channels
- Depolarisation
- Release of NT
- Inhibitory force closes ion channels
What are auditory pathways?
- Highly complicated pathways
* Each hemisphere of the brain processes auditory information from both sides (ipsilateral and contralateral)
Auditory cortices are organized ___________.
tonotopically
by frequency
Describe the auditory core region.
- neurons within each of the auditory core regions are arranged into a tonotopic map
- with characteristic frequencies that gradually shift from low at one end to high at the other end
Describe the auditory pathway
auditory nerve –> cochlear nucleus –> trapezoid body –> superior olivary complex –> inferior colliculus
-> medial geniculate body –> auditory cortex
Name the two auditory cortices
ipsilateral auditory cortex
contralateral auditory cortex
Ventral pathway a.k.a.?
“what” pathway
Dorsal pathway a.k.a.?
“where” pathway
STG
superior
temporal
gyrus
Ventral pathway I
STG > BA 45 (Broca’s Area)
Ventral pathway II
antSTG > FOP
Dorsal pathway I
pSTG > premotor cortex
Dorsal pathway II
pSTG > BA 44
Where is low pitch detected?
apical region
Where is high pitch detected?
basal region
Name the two types of frequency coding…
Place coding (high and medial frequencies) Temporal coding (low frequencies)
Loudness: name the hypothesis
firing rate hypothesis
Describe the firing rate hypothesis
The rising (high pressure) phase of each cycle of the sound signal evokes bursts of spikes in a collection of auditory nerve fibres.
Location depends on…
- Intensity (high frequencies)
* Speed of the sound (low frequencies)
What is ITD and IID?
interaural time difference
interaural intensity difference
What is speech?
process to…
- understand spoken and printed words
- express ideas in speech and writing
How is speech produced?
- movements of vocal cords
- - during expiration
Describe the mechanisms of speech.
- Hearing sound – Auditory pathways and auditory cortex
- Understand the heard sound
- Express ideas in speech
Name the areas of the brain that are receptive for speech.
Primary auditory cortex
Angular gyrus
Wernicke’s area
Name the functions of WERNICKE’S AREA
- Process sensory information from somatic sensory, visual, and auditory cortices
- Essential for comprehension, recognition and construction of words and language
- Perception of spoken language
Name the two executive brain areas of speech.
Broca’s area
Primary motor cortex
Broca’s area: name the functions
- Regulation of muscles of lips, tongue, pharynx and larynx
* Receives information from Wernicke’s area and processes the information into detailed and coordinated patterns
Primary motor cortex: name the function
– initiates movement of lips, tongue and larynx to produce spoken speech
Name three speech disorders.
- Aphasia
- Dysarthria
- Aphonia
Describe Aphasia
Loss or impairment of production and/or comprehension of spoken or written language
Mostly to acquired lesions of brain
Describe Dysarthria
- impairments in articulation of speech
- - intact mental function and comprehension of spoken & written speech
Describe Aphonia
loss of voice due to disorder of larynx
