Lecture 8 - Audition Flashcards
What are the steps on the auditory pathway?
cochlear nucleus (starting point) –> superior olivary complex –> lateral lemniscus—-> inferior colliculi—>medial lemniscus—-> auditory cortex (A1)
How many auditory fields are in each ear?
Two
What are the two ways that human beings localize sound?
frequency and intensity
Which section of the auditory system do humans detect speech?
parabelt (i.e., the secondary auditory cortex or A2)
Which section of the auditory system do humans detect sounds (include their frequencies and intensities)?
Core (i.e., Heschl gyrus or Brodmann area 41 or the primary auditory cortex A1)
What does the parabelt and belt consist of?
belt = Wernicke’s area (Auditory association 2 or Brodmann area 42 ), Brodmann areas 39, inferior parietal lobule, anterior superior temporal gyrus, posterior temporal gyrus, parietal and temporal bords, Brodmann area 22, and the entire superior, middle, and inferior temporal gyrus
What is ABR? What does it do?
Auditory Brain Response - a test to determine if the cochlea is functioning properly; it records brain waves that respond to sounds heard through earphones.
In ABR, auditory middle latency ERP (Evoked Response Potentials) refers to
P 20-50 ms- thalamus - medial geniculate nucleus
What are signs that there is a lesion in the medial geniculate nucleus?
no effect indicated on the speech recognition test; opposite ear has poorer hearing based on the dichotic listening test; ABR is normal/ no effect; indications of middle and late potentials (i.e., auditory info has reached the thalamus)
What is the first site of crossover in the auditory pathway?
At the superior olivary complex
What is the crossover of auditory information?
sound information is carried on both sides of the pathway
What is the function of the inferior colliculus?
locates sound, determines frequency, and combines auditory systems with nonauditory systems
Which part of the auditory system is there only unilateral representation of sound in the CNS?
cochlear nuclei
What is the medial geniculate nucleus?
nuclei found in the thalamus that sends binaural information from the inferior colliculus to the auditory cortex. It has polysensory neurons.
What parts of the brain does the medial geniculate nucles receive information from?
inferior colliculus and pontine reticular
What locations of the brain may the medial geniculate nucleus send auditory information to?
auditory cortex and pulvinar nuclei of the thalamus
What is the pulvinar nuclei of the thalamus known for?
associated with attention
What is the perisylvian fissure important for?
taking what humans hear and perceiving it as phonemes
What is one fact about the auditory core cortex?
There is more than one space that responds to different tones and in different orders. There are many representations of frequency in each area of the auditory core cortex.
What are signs that there’s a lesion at the superior olivary complex?
pure tone test and speech recognition test are both within normal limits; masking difference levels (tests sound localization) is poor, in ABR a wave is delayed; sound localization is poor in both auditory fields
What are signs that there’s a lesion at the medial geniculate nucleus?
speech recognition test is within normal limits; dichotic listening test is poorer in the right ear, frequency patterns (non-speech) poor in both ears; ABR is WNL
The planum temporale is larger in which hemisphere and is found where?
left hemispehere, belt portion
Who diagnoses someone with APD or auditory processing disorder? What should an evaluation of someone suspected to have APD include?
audiologists; it should include verbal and nonverbal tests
Selective attention to sounds occurs at the _____ and ______
thalamus (pulvinar nuclei) and inferior colliculi
Cochlear nuclei are found in the ______
medulla
The retrocochlear pathway consists of _____
hair cells –> bipolar cells in spiral ganglion —-> through central processes to form acoustic branch (this is CN VIII) —> cochlear nuclei in the medulla
The inferior colliculus is found in the _____
midbrain
The geniculocortical fibers are found in the ______
internal capsule
What part of the brain sends much information to the inferior colliculus?
cerebellum
The cochlear nuclei sends auditory information to the ______
superior olivary complex contralaterally
The superior olivary complex sends information via _______ ipsilaterally and contralaterally to ___, ___, and ___. It has both excitatory and inhibitory neurons.
olivocochlear bundle; cochlear nuclei, cochlea, and CN VIII
To coordinate head and neck and to establish equilibrium, the inferior colliculi communicates with the superior colliculi via _____
CN III (oculomotor)
To coordinate head and neck and to establish equilibrium, the superior olivary complex communicates with the medial longitudial nerve via _____
CN IV (trochlear) and CN VI (abducens)
To coordinate head and neck and to establish equilibrium, the auditory and vestibular branches of _____ communicate with the ______
CN VIII; cerebellum
Neurons in both the ____ and ____ are sensitive to differences in time and frequency.
superior olivary complex and cochlea
Sound shadow affects ______ sounds.
high frequency sounds; makes them softer
Sound shadow does not affect ____ sounds
low frequency
Time difference impacts ______ sounds
low frequency
A monaural hearing loss is caused by a lesion to the
Auditory nerve (CN VIII)
