Auditory Pathways

Question 1

There is primarily ____ with ____ innervation of the inner hair cells and primarily ____ innervation with _____ of the outer hair cells.

Outer hair cells control the ____. The vibration of the tectorial membrane over the inner hair cells relays ____ info to the ____.

Answer 1

Afferent; efferent

Efferent; afferent

Tectorial membrane (its strength and position); afferent; spiral ganglion

Question 2

The cochlea has a tonotopic orientation of the helicotrema and is where most of the ___ sounds are interpreted; the base is where the ____ sounds are interpreted.

Answer 2

Low frequency

High frequency

Question 3

The ____ is the only part of the pathways that is unilateral.

After the cochlear nucleus, it becomes ____.

Lesion in the cochlear nucleus leads to ____. After the cochlear nucleus, all the fibers desiccate and we cannot tell where a lesion is coming from.

Answer 3

Cochlear nucleus

Bilateral

Single-sided deafness

Question 4

Nearby masses that affect the restiform body, facial nucleus, etc. will also affect the _____.

Lesions of the cochlear nucleus result in _____ deficits.

Answer 4

Cochlear nucleus

Unilateral

Question 5

The afferent/efferent fibers leave the cochlea, travel through the cochlear N, and synapse in the ____.

What are the two parts of the anterior cochlear nucleus?

Answer 5

Cochlear nucleus: posterior and anterior parts

Ventral posterior cochlear nucleus
Ventral anterior cochlear nucleus (tonotopically oriented)

Question 6

First order neurons are the ____ in the ____.

First order neurons run from the inner and outer hair cells to the ____, then to the ____.

Answer 6

Spiral ganglion (bipolar); cochlea

Spiral ganglion; anterior ventral cochlear nucleus, dorsal cochlear nucleus, and ventral posterior cochlear nucleus

Question 7

The dorsal cochlear nucleus contains what cells?

Fx?

Answer 7

Pyramidal cells, stellate cells

These cells send afferent projections to the fourth order neurons in the upper part of the pons (lateral lemniscus nucleus); this projection is called the dorsal acoustic stria

Question 8

The ventral posterior cochlear nucleus sends afferent projections to ____ via the ____.

Answer 8

Fourth order neurons in the upper portion of the pons (lateral lemniscus nucleus); intermediate acoustic stria

Question 9

The anterior ventral cochlear nucleus is the _____. It goes to the third order neurons (superior olivary nucleus) via the ___.

What cells does this nucleus contain?

Answer 9

Primary projecting pathway

Ventral acoustic stria (trapezoid body)

Stellate/bushy cells

Question 10

The ____ are the first point in the pathways where the fibers are crossing the midline.

Answer 10

Acoustic striae

Question 11

The superior olivary nucleus projects to the _____.

The ____ projects to the inferior colliculus too.

The ___ will bypass the lateral lemniscus nucleus to go to the inferior colliculus.

____ will also send fibers to the inferior colliculus.

Answer 11

Inferior colliculus

Ventral acoustic stria (trapezoid body)

Dorsal acoustic stria

Lateral lemniscus nucleus

Question 12

The ____ is a tract of ascending neurons bypassing the superior olivary nucleus and the lateral lemniscus nucleus to get to the inferior colliculus.

The ____ is a housing point for nuclei of neurons.

If you damage any one of the nuclei, ___.

Answer 12

Lateral leminiscus

Lateral leminiscus nucleus

There would still be ascending info to the brain.

Question 13

The neurons from the inferior colliculus will send fibers up to the ____ in the thalamus. This connects the ____.

Info from the medial geniculate nucleus will then be sent to the ____.

Answer 13

Medial geniculate nucleus

Brachium of the inferior colliculus

Auditory cortex in the transverse temporal gyri (transverse gyrus of Heschl)

Question 14

The inferior colliculus has ____.

The ascending fibers (trapezoid body) from the anterior ventral cochlear nucleus synapse in specific parts of the ____ based on its tonotopic mapping.

Then theses fibers will then synapse in the ____ to the medial geniculate nucleus in a tonotopic mapping as well.

Answer 14

Tonotopic mapping

Inferior colliculus

Brachium if the inferior colliculus

Question 15

The auditory cortex is ____. It gives the ability to understand ____.

____ in the temporal lobe gives the ability to hear and understand speech.

Auditory agnosia is different than Wernicke’s aphasia…why?

Answer 15

Tonotopically mapped (interior is high frequency, exterior is low); sounds

Wernicke’s area (area 22)

Auditory agnosia: hear sound but have no idea what the sound is

Wernicke’s aphasia: hear speech but have no idea what is being said

Question 16

The ____ transmits the understanding of speech from Wernicke’s area (area 22) to Broca’s area (area 44/45).

What is Broca’s aphasia?

Answer 16

Arcuate fasciculus

Pt can understand sound (Wernicke’s okay) but pt cannot formulate the words to answer back

Question 17

The superior olivary nucleus radiates ____ and ___ fibers.

What are the two parts of the superior olivary nucleus? Fx?

The ____ sends inhibitory neurons to the opposing medial superior olivary nucleus.

Answer 17

Afferent and efferent

Medial superior olivary nucleus: allows the understanding of localization of sound based on timing (can tell if sound is coming from L or R)

Lateral superior olivary nucleus: allows the understanding of the intensity of sound (coincidence detection)

Trapezoid body

Question 18

The ____ projects from the superior olivary nucleus, through the ____ to the outer hair cells to elongate them and dampen sounds -> projection reflex.

Answer 18

Olivocochlear bundle

Cochlear N

Question 19

The ____ is next to the superior olivary nucleus.

The superior olivary nucleus sends fibers to the facial nucleus to the ____. This allows for the ____ reflex.

Answer 19

Facial nucleus

Stapedius muscle

Stapedius

Question 20

When you hear sound, Brodmann’s area 41, 42, and 22 send efferent fibers into the ____ to induce postural change to look over to the sound that you hear.

Answer 20

Tectobulbospinal tract

Question 21

Tuning fork on head will send sound to both ears. The ____ will tell the brain where the sound is coming from.

If there is a compromise of sensory info, sound will be lateralized to the ___.

If the stapes is not moving correctly in the cochlea, the hair cells will not be stimulated, and there will be ____.

If there is sensoryneural loss, there is a lesion from the _____.

Answer 21

Medial superior olivary nucleus

Contralateral ear

Conductive hearing loss

Cochlear to the cochlear nucleus.

Question 22

In the Webber Renee test, sound will lateralize to the RIGHT meaning…..?

Answer 22

There is sensoryneural loss in the L ear (contralateral) or conductive loss in the R ear

In the side the sound lateralizes to, the tuning fork is either doing the work of the stapes or the nerve is doing better

Question 23

The _____ contains axons from only 2nd, 3rd, and 4th order neurons.

Answer 23

Lateral lemniscus nucleus

Question 24

_____ is the connection between the cochlear nucleus and the superior olivary nucleus.

____ is the only way to get to the inferior colliculus.

Answer 24

Trapezoid body (ventral acoustic stria)

Lateral lemniscus