1 - Auditory Pathway Flashcards
The 1st order neuron for the auditory pathway comes from the primary afferent CN VIII cochlear part. Its cell bodies lie in the ________ _______, which is within the cochlea. The neuron enters brainstem at the ________ ________ where it divides into ascending and descending bundles.
Spiral Ganglion
Pontomedullary Junction
The ascending and descending bundles of the auditory pathway will synapse in the…
Dorsal Cochlear Nuclei
Ventral Cochlear Nuclei
Ascending bundles synapse in the (ANTERIOR/POSTERIOR) subdivision of the (VENTRAL/DORSAL) Cochlear Nucleus.
Anterior
Ventral
Descending bundles synapse in the (ANTERIOR/POSTERIOR) subdivision of the (VENTRAL/DORSAL) Cochlear Nucleus, and in the (VENTRAL/DORSAL) Cochlear Nucleus.
Posterior
Ventral
Dorsal
_________ information is about sounds at a single ear. It is routed to the _________ side.
Monaural
Contralateral
Describe the pathway of the Monaural Tract.
1st order neuron cell bodies in Spiral Ganglion —
Synapse in Dorsal Cochlear Nucleus —
Cell bodies in Dorsal Cochlear Nucleus —
Axons cross to the contralateral side via the Dorsal Acoustic Stria —
Ascend in the Lateral Lemniscus —
Synapse in Inferior Colliculus (nuclei of lateral lemniscus) —
Cell bodies in Inferior Colliculi —
Axons travel via the brachium of Inferior Colliculi to the Medial Geniculate Nucleus (MGN) —
Synapse in MGN —
Cell bodies in MGN —
Axons pass through Sublenticular Limb of Internal Capsule —
Synapse in layer IV of Primary Auditory Cortex (Heschl’s Gyrus)
________ information is about differences between sounds at both ears. It is handled by central pathways that receive, compare, and transmit this input.
Binaural
Describe the pathway of the Binaural Tract.
1st order neuron cell bodies in Spiral Ganglion —
Synapse in Ventral Cochlear Nucleus —
Cell bodies in Ventral Cochlear Nucleus (either posterior or anterior) —
Axons project bilaterally passing through Trapezoid body —
Synapse in Superior Olivary Complex (Medial and Lateral nucleus) —
Cell bodies in Medial and Lateral superior olivary nuclei —
Ascend in the Lateral Lemniscus —
Synapse in Inferior Colliculi (nucleus of lateral lemniscus) —
Cell bodies in the Inferior Colliculus —
Axons travel via the brachium of the Inferior Colliculus to the Medial Geniculate Nucleus —
Synapse in MGN —
Cell bodies in MGN —
Axons pass through Sublenticular Limb of Internal Capsule —
Synapse in layer IV of the Primary Auditory Cortex (Heschl’s Gyrus)
In the Binaural Tract, do the fibers go ipsilateral or contralateral?
Both, because it goes bilaterally from the Ventral Cochlear Nucleus then some fibers will stay ipsilateral and some will cross and move contralateral.
What are the three types of deafness?
Conduction
Sensorineural (Nerve)
Central
This type of deafness is due to a deficit related to an obstructed, or altered, transformation of sound to the tympanic membrane or through the ossicle chain (i.e., too much ear wax, ruptured tympanic membrane from ear infection, etc).
Conduction Deafness
This type of deafness is a result from damage to the cochlea (i.e., hair cells), the cochlear part of CN VIII, or to the cochlear nuclei. Causes ipsilateral deafness.
Sensorineural (Nerve) Deafness
This type of deafness is caused by damage to the central pathways. This occurs anywhere past the cochlear nuclei, and does not result in complete deafness because of crossing interneurons. Patients will have trouble localizing where sound is from and lose attention to stimuli.
Central Deafness
This is the origin of blood supply to the cochlea and the auditory nuclei of the pons and medulla.
Basilar A.
This artery, usually a branch of the AICA, supplies the inner ear and the cochlear nuclei.
Labyrinthine (Internal Auditory) A.
What happens when there is an occlusion of the AICA?
Results in a monaural hearing loss (ipsilateral)
If there is an occlusion of the _______, this lesion may also damage the emerging fibers of the Facial N. and the pontine gaze center, resulting in monaural deafness combined with ipsilateral facial paralysis and an inability to look toward the side of the lesion.
AICA
This gives blood supply to the Superior Olivary Complex and Lateral Lemniscus.
Short Circumferential Branches of the Basilar A.
These arteries supply the Inferior Colliculus.
Superior Cerebellar A.
Quadrigeminal As.
This artery supplies the Medial Geniculate bodies.
Thalamogeniculate As.
This artery supplies the Primary Auditory and Association Cortices.
M2 segment of the Middle Cerebral A.
T/F. You have to be able to see or hear in order to fully understand language.
False. You don’t need vision or sound for language to work, it is its own entity.
This hemisphere is the dominant hemisphere (in 94 percent of adults).
Left hemisphere
These are two areas within the left (dominant) hemisphere.
Wernicke’s
Broca’s
This area is responsible for the comprehension of spoken and written language.
Wernicke’s