Auditory tracts

Question 1

How is the auditory information divided as it enters the brainstem via CN VIII

Answer 1

Auditory information coming from the spiral ganglion will enter the brainstem via the pontomedullary junction and divide into ascending and descending bundles as it synapses on the cochlear nuclei

Question 2

where does the ascending bundles synapse in the cochlear nuclei

Answer 2

ascending information synapses in the anterior subdivision of the ventral cochlear nucleus

Question 3

Where does the descending bundles synapse in the cochlear nuclei

Answer 3

descending bundle synapses in the posterior subdivision of the ventral cochlear nucleus and in the Dorsal cochlear nucleus

Question 4

Monaural Tract pathway and what information is carried

Answer 4

Monaural information is information about sounds at a single ear and is then routed to the contralateral side of the brain

• Cell bodies in the dorsal cochlear nucleus cross to the contralateral side via the dorsal acoustic stria
• Ascend in the lateral lemiscus to synapse in the inferior colliculus
• cell bodies in the inferior colliculus then have their axons travel through the brachium of the inferior colliculus to the medial genticulate nucleus
• Cell bodies from the medial geniculate nucleus will send their axons through the sublenticular limb of the internal capsule to layer IV of the primary auditory cortex

Question 5

Binaural Tract pathway and what information is carried

Answer 5

Binaural information carries differences between sounds at both ears and is handled by central pathways that recieve, compare, and transmit this input

• Cell bodies in the ventral cochlear nucleus project bilaterally passing through the trapezoid body to the superior olivary complex (nucleus)
• the axons from the cell bodies in the medial and lateral superior olivary nucleus ascend in the lateral lemniscus to the inferior colliculus
• cell bodies in the inferior colliculus then send their axons through the brachium of the inferior collicuus to the medial genticulate nucleus and synapse their
• The cell bodies in the medial geniculate nucleus will then send their axons through the sublenticular limb of the internal capsule to layer IV of the primary auditory cortex

Question 6

What is significant about all the crossing over of auditory information in the central pathways

Answer 6

If their is damage in the central pathways normally their is no deafness because information crosses over from each ear

Question 7

What are the 3 types of deafness

Answer 7

Conduction: deficit related to an obsftructed or altered transformation of sound to the tympanic membrane (ipsilateral deafness)

Sensorineural: results from damage to the cochlea, the cochlear part of the CN VIII or to the cochlear nuclei (ipsilateral deafness)

Central: damage to the central pathways

• results in no deafness
• difficulty localizing where the sound is coming from
• difficulty picking out sound in a noisy area
• dont notice certain sound stimuli

Question 8

Where does the majority of the blood supply to the cochlea and the auditory nuclei come from

Answer 8

Branches of the basilar artery

Question 9

WHat does the Internal auditory artery supply and what happens if their is an occlusion in the AICA

Answer 9

also called the labyrinthine artery which is a branch of AICA

supplies the inner ear and the cochlear nuclei

occulusion of the AICA will result in monaural hearing loss and may lead to damaging the facial nerve or the pontine gaze center, giving facial paralysis and inabillity to look toward the side of the lesion

Question 10

What does the short circumferential branches of the basilar supply

Answer 10

superior olivary nucleus and lateral lemniscus

Question 11

What does the superior cerebellar and the quadrigeminal artery supply

Answer 11

supplies the inferior colliculus

Question 12

What does the thalamogeniculare aretery supply

Answer 12

supplies the medial geniculate bodies

Question 13

What does the M2 segment of the middle cerebral artery supply

Answer 13

supplies the primary auditory and association cortices

Question 14

Which hemisphere is the dominant hemisphere

Answer 14

the side that processes language 94 percent of people are left hemisphere dominant

Question 15

What does Wernickes area do

Answer 15

comprehension of spoken and written language

Question 16

What does Brocas area do

Answer 16

Instruction for language output
planning the movements to produce speech (word production and grammer)
Providing grammatical function of words

Question 17

What does the right hemisphere do in areas analgous to brocas and wernickes

Answer 17

Area analagous to Wernickes: Interpreting nonverbal signals from other people (body language)

Area analagous to Brocas: Instructions for producing non-verbal communication including emotional gestures and intonation of speech
-adding extra emotional meaning to how we say words

Question 18

What is the order of language information travel in the brain

Answer 18

Primary auditory cortex (auditory discrimination)

Auditory association cortex (classification of sounds, language vs other sounds)

Wernickes area (auditory comprehension, vocabulary)

Subcortical connections (link wernickes and brocas area)

Brocas area (instructions for language output)

Oral and throat region of sensorimotor cortex (cortical output to speech muscles)

Question 19

What is the lateral temporal cortex important for

Answer 19

Semantic knowledge: meaning of a sentence
word recognition (meaning)

Question 20

What are the arcuate fasciculations important for

Answer 20

word repetition

Question 21

What happens if their is damage to the sensory association cortex or the lateral temporal cortex

Answer 21

Auditory agnosia

inabillity to describe a sound that has been heard
must affect it bilaterally

Question 22

Wernickes area lesion

Answer 22

Wernickes aphasia (receptive or fluent aphasia)

defect of the comprehension of language
unable to understand what is said to them
alexia: unable to read
agraphia: unabe to write comprehensible language
display fluent paraphasic speech

arent aware of there issue

Question 23

Brocas area lesion

Answer 23

Brocas aphasia or expressive aphasia or non-fluent aphasia

loss of the abillity to speak fluently
can understand spoken and written language

most severe form makes an individual mute

less severe: short habitual phrases
speech is slow, labored, poor enunciation
nonessential words are omitted

Question 24

Global Lesion

Answer 24

type of non fluent aphasia

lesion of lateral sulcus (both wernickes and brocas are hit)

receptive and expressive defects
reading and writing impaired

Question 25

Fluency, Grammar, Comprehension, Naming, Repetition, lesion: Broca

Answer 25

Fluency: Non fluent
Grammar: Impaired
Comprehension: IMpaired for complex sentences
Naming: Preserved
Repetition: Impaired for complex sentences
Lesion: Left inferior frontal gyrus (Broca area and surroundings)

Question 26

Fluency, Grammar, Comprehension, Naming, Repetition, lesion: Wernicke

Answer 26

Fluency: Fluent
Grammar: may be normal
Comprehension: Impaired for single words
Naming: IMpaired
Repition: IMpaired for single words
Lesion: Left superior temporal gyrus, inferior parietal lobe, posterior middle temporal gyrus, middle temporal gyrus

Question 27

Fluency, Grammar, Comprehension, Naming, Repetition, lesion: Conduction

Answer 27

FLuency: FLuent
Grammar: PReserved
Comprehension: normal
Naming: preserved
Repetition: impaired
Lesion: arcuate fasciculations

Question 28

Fluency, Grammar, Comprehension, Naming, Repetition, lesion: Transcortical motor

Answer 28

Fluency: Nonfluent
Grammar: preserved
Comprehension: normal
Naming: preserved
Repetition: preserved
Lesion: ACA-MCA border zone infarction

Question 29

Fluency, Grammar, Comprehension, Naming, Repetition, lesion: Transcortical sensory

Answer 29

Fluency: Fluent
Grammar: Preserved
Comprehension: impaired
Naming: impaired
Repetition: preserved
Lesion: MCA-PCA border zone