Chapter 7: AUDITION Flashcards
Speed of noise?
1200 km per hour
three dimensions of sound?
- pitch
- loudness
- timbre
pitch?
- frequency of vibration
- measured in hertz
loudness?
intensity
timbre?
complexity
How does sound travel through the outer ear?
pinna–>tympanic membrane (eardrum)
components of middle ear?
- ossicles
- malleus (hammer)
- incus (anvil)
- stapes (stirrup)
- oval window
ossicles?
- bones of the middle ear
- set into vibration by the tympanic membrane
malleus?
-transmits vibration via the incus and stapes to the cochlea
cochlea?
- liquid-filled
- sound transmitted through air is transferred to cochlea
- divided into three sections (see paper)
organ of Corti?
- receptive organ
- consists of basiliar membrane, hair cells, tectorial membrane
How does the basiliar membrane respond to sound’
- bends
- high frequency: base of the membrane bends
- low frequency: apex of the membrane bends
How is auditory information transmitted to the brain by hair cells?
- Hair cells form synapses with dendrites of neurons whose axons bring auditory info to the brain
- tension on tip links open ion channels, membrane depolarizes, hair cells release neurotransmitters.
cochlear nerve?
The branch of the auditory nerve that transmits auditory information from the cochlea to the brain.
superior olivary complex?
group of nuclei in the medulla; involved with auditory functions, including localization of the source of sounds
lateral lemniscus?
- bundle of fibers
- run rostrally through medulla and pons
- carries fibers of the auditory system
tonotopic representation?
-topographically organised mapping of different frequencies of sound that are represented in a particular region of the brain
core region?
- The primary auditory cortex
- located on a gyrus on the dorsal surface of the temporal lobe
belt region?
- first level of auditory association cortex
- surrounds the primary auditory cortex
parabelt region ?
- second level of auditory association cortex
- surrounds the belt region
anterior stream of the auditory association cortex?
- complex sounds
- begins in anterior parabelt region
posterior stream of the auditory association cortex?
- localization of sound
- begins in the posterior parabelt region.
place code?
- moderate to high frequencies
- info about diff frequencies is coded by diff locations on the basiliar membrane.
rate code?
- low frequencies
- info about diff frequencies is coded by the rate of firing of neurons in the auditory system.
cochlear implant?
-electronic device surgically implanted in the inner ear that can stimulate the basilar membrane
How is loudness perceived?
- cochlear nerve alters rate of firing
- produces more intense. vibration so more intense shearing force on the cilia
- more nt release
How is the loudness of low frequency perceived?
-signaled by the number of axons arising from the neurons in the basilar membrane
fundamental frequency?
- aspect of timbre
- Lowest and usually most intense, frequency of a complex sound
- most often perceived as the sound’s basic pitch
overtone?
- aspect of timbre
- frequency of complex tones that occurs at multiples of the fundamental frequency
overtone?
- aspect of timbre
- frequency of complex tones that occurs at multiples of the fundamental frequency
What does the auditory cortex do in the perception of timbre?
-the auditory cortex analyses a complex sequence of multiple frequencies that appear, change in amplitude, and disappear.
phase differences?
- low frequencies
- the diff in arrival times of sound waves at each of the eardrums
intensity difference?
- high frequencies
- the difference in sound intensities at each of the eardrums.
analysis of timbre?
- to determine the height and if it is in front or behind us
- angle of sound waves striking the folds and ridges of outer ear.
perception of identity?
- one pattern of recognition
- activated in the anterior stream
perception of location?
- one pattern recognition
- activated in the posterior stream
