Module 4 - Audition Flashcards
what is the medial geniculate nucleus
major thalamic region associated with audition
allows for complex sound perception
gets info from both inferior colliculi
location of the primary auditory cortex
within Heschl’s gyrus and surrounded by secondary areas
what percentage of auditory pathways are ipsilateral and contralateral
40% ipsilateral and 60% contralateral
what is cochlear nucleus responsible for?
frequency
on/off functions
intensity
what is trapezoid body responsible for?
direction
what is superior olivary complex responsible for?
combines info from both ears for localization/direction purposes
what is the inferior colliculus responsible for?
attention
reflexive response
what is planum temporal associated with? what is another name for it?
language
Wernicke’s area
Is the left or right planum temporal larger? (wernicke’s area)
left is larger in all right-handed people
(and 70% of left handed)
Is the left or right Heschl’s gyrus larger
right is larger
what is the insula
contains regions related to language and taste perception
what does pitch perception correspond with?
frequency of sound waves
hair cells in cochlea code frequency as function of ___
location on basilar membrane
what type of frequency waves maximally displaces hair cell cilia at base of cochlea?
high frequency waves
results in high pitched noises
what type of frequency waves maximally displaces hair cell cilia at apex of cochlea?
low frequency waves
results in low pitched noises
how many hair cells are each bipolar cell connected to? what does this mean?
one
therefore info is conveyed about only one spot on basilar membrane
can hair cells respond to frequencies other than the one that maximally displaces them?
yes, if amplitude is large enough
what does the anterior end of primary auditory cortex correspond with?
apex of cochlea hence low frequencies
what does the posterior end of the primary auditory cortex correspond with?
the base of the cochlea hence high frequencies
what do neurons code for
pitch
location
loudness
patterns
what codes pitch
hair cell cilia on basilar membrane
what are cochlear implants
electronic devices surgically inserted in inner ear to help deaf people hear
captures sound via microphone. processor converts frequencies into electric current and stimulates locations on basilar membrane
do bipolar cells fire more when louder or quieter
fire more with louder sounds
what is the intensity of sound waves in terms of loudness matched by?
vibrations on basilar membrane
what is loudness measured in?
decibels
what is pitch measured in
hertz
what is loudness associated with
amplitude of sound wave
what are the different levels of loudness?
threshold = softest humans can detect (0)
normal = between 40-60
damaging/prolonged sounds = 100 and above
what two mechanisms are used to detect loudness?
intramural time difference and intramural intensity time difference
provided by cochlear nerve synapses on either side of the brain
what is intramural time difference? where is the process carried out?
neurons in brainstem computing the difference in a sound wave’s arrival time in each ear
arrival computation determined in superior olivary complex
what happens if sound source is right in front of us? (not off to the side) using intramural time difference mechanism?
ITD becomes smaller until there is no difference
results in turning head allowing sound waves to strike one ear sooner
what is interaural intensity difference? where is it carried out?
used to detect the source of sound by utilizing the sound’s relative loudness on left/right side
higher freq waves on one side of head are louder than on the other
superior olive and trapezoid bodies calculate difference
what happens if sound source is right in front of us (not off to side) using intraural intensity difference?
head must be tilted to detect sound difference just like ITD
what happens if sound source is right in front of us (not off to side) using intraural intensity difference?
head must be tilted to detect sound difference just like ITD
what two pathways do humans have for audition?
dorsal and ventral
what occurs in the neurons of ventral auditory pathway
decode complex sounds (referred to as auditory object recognition)
spectral complexity
what occurs in the neurons of the dorsal auditory pathway
integrating auditory and somatosensory information
what hemisphere does music ability take place in
right hemisphere
are languages more similar or different
similar, even though multiple languages may be difficult to learn
what did Chomsky discover
humans have innate capacity for language
is human language genetic/innate? why?
universal in all populations
children learn language early in life easily (don’t really need to be taught, learn through observation)
languages have common structural elements (syntaxes, have grammar, etc.)
describe Broca’s research (experiment + conclusions)
examined dead patients who had trouble with speech
confirmed that certain language functions located in left frontal lobe due due to this area being damaged
area known as Broca’s area
what is Broca’s Area
left hemisphere speech area that functions with motor cortex to produce movements needed for speaking
describe Wernicke’s research (experiment + conclusions)
examined patients with difficulty understanding langauge
identified posterior left temporal lobe (planum temporal) to be a speech zone
known as Wernicke’s area
what is Wernicke’s area
area associated with language comprehension
Wernicke’s aphasia
can speak fluently, but their language makes little sense
Broca’s aphasia
cannot speak despite having normal comprehension/physiology because they cannot make the movements required to talk
what connects Broca’s and Wernicke’s areas
arcuate fasciculus
what is double dissociation
method for showing that two areas of neocortex are functionally dissociated
two different behavioural tests used - each must be affected by damage in one area, but not another
what is Wernicke’s model
thought - wernicke’s area - Broca’s area - facial area of motor cortex - cranial nerves - speak
describes idea that Broca’s and Wernicke’s work together to allow speaking
what did Penfield come up with in terms of brain mapping
engaged in brain stimulation on awake patients during surgery
what did Penfield discover
that Broca’s area is not the independent site of speech production and Wernicke’s area is not the independent site of language comp
what four areas did penfield identify?
broca’s area
wernicke’s area
dorsal region of frontal lobe (supplementary language area)
motor/somatosensory areas for mouth and tongue
effects on speech vary by region, but damage to any disrupts speech in some way
what is PET
brain-imaging technique that detects changes in blood flow
used to study metabolic activity of brain cells engaged in tasks
describe outcomes of Zatorre’s research
listening to bursts of noise activates primary auditory cortex
listening to words activates Wernicke’s area
discriminating speech sounds activates Broca’s area
what is A1 primarily responsible for
analyzes all incoming auditory signals, speech and non speech
what are secondary auditory areas responsible for
higher order signal processing required for things like analyzing language sound patterns
in what hemisphere does music processing take place
right hemisphere
in what hemisphere does language processing take place
left. hemisphere
describe Ravel case study
developed aphasia due to brain disorder caused by stroke/blow to head in left hemisphere
many musical skills still in tact because localized to right hemisphere (ex. recognizing melodies)
some abilities gone (like producing music)
where does production of music take place in brain
playing writing and composing seem to be localized to left hemisphere
where does perception/recognition of music take place in brain
right hemisphere
where does listening to bursts of noise take place in brain
Heschl’s gyrus
where does listening to melodies take place in brain
A2
where does comparing pitches take place in brain
frontal lobe
who is music therapy most useful for
people post stroke or Parkinson’s
why is music therapy helpful
listening to rhythm activates motor areas and improves gait/arm movements
reduces pain perception and medication use after surgery
improves mood in depression/post-traumatic injury patients
enhances ability to distinguish speech sounds
what are otoacoustic emissions
spontaneous/evoked sound waves produced within ear by cochlea
what are spontaneous otoacoustic emissions
occur without external stimulation
what are evoked otoacoustic emissions
generated in response to sound waves
useful to assessing hearing impairments
what is echolocation
ability to use sound to locate objects in space
what happens as a result of left-hem dysfunction
seizures
what is a seizure
involves losing consciousness, and engaging in repetitive behaviours
solved by medication, or surgery
what is amnusia
tone deaf - inability to distinguish between musical notes
