Auditory Tracts Flashcards
Draw the Monoaural Auditory tract
Ok
What type of information does the monoaural tract transmit?
Sounds from single ear
Draw the binaural tracts
Ok
What type of info do binaural tracts transmit?
Differences between sounds at both ears
Where doe the monoaural and binaural tract synapse at in the cortex?
Layer IV of primary auditory cortex in the anterior transverse temporal gyrus
Is there tonotopical organization in the auditory tracts?
Yes, high and low pitched sounds are organized tonotopically in these tracts
What happens at the olive, lateral lemniscus and inferior colliculus in the auditory tracts?
Further crossing over of some of the fibers, so hitting a side of the tract isn’t gonna cause total deafness because of this “insurance”
What is conduction deafness?
Deafness from obstructed, altered TM or ossicle chain
Ipsilateral ear is affected
What is sensorineural nerve deafness?
Deafness due to damage to cochlea, cochlear part of CN VIII or cochlear nuclei
Ipsilateral ear is affected
What is central deafness?
Damage to the central pathways after the Cochlear nucleus
Does NOT result in deafness due to the crossing over, but can have trouble with sound localization/focus
What does the basilar artery supply?
Cochlea and auditory nuclei of pons and medulla
What does the internal auditory (labyrinthine) artery supply?
From AICA, supplies inner ear and cochlear nuclei
What happens when AICA is occluded?
Monoaural (one ear) hearing loss.
Can also damage the facial nerve and the pontine (horizontal) gaze center, so you can have ipsilateral facial paralysis and inability to look toward side of lesion
What does the short circumferential branches of basilar supply?
Superior olivary complex and lateral lemniscus
What does the superior cerebellar and quadrigeminal arteries supply?
Inferior colliculus
