Auditory Paths SD Kongs Flashcards
The cochlear nerve enters the brainstem at the cerebellopontine angle and split into ascending and descending bundles. Where do the ascending bundle fibers go?
To the anterior part of the anteior cochlear nucleus
The cochlear nerve enters the brainstem at the cerebellopontine angle and splits into two bundles. Where do the fibers of the descending bundle travel?
- Posterior part of the anterior cochlear nucleus
- Posterior part of the posterior cochelar nucleus
Describe the path sound takes in the monaural path?
This path takes in sound from one ear and routes it contralaterally.
- Begins in the posterior cochlear nuclei
- Travels in the acoustic stria to the contralateral side
- Synapses in the Lateral Lemniscus
- Travels to the inferior colliculus
- To the MGN
- To the primary auditory cortex
Describe the path sound takes in the Binaural tract and what is the purpose of this tract?
This tract takes sound from both ears and compares it. There is a lot of crossing and crossing back over.
- Anterior cochlear nucleus sends fibers either ipsilaterally or contralaterally.
- contralateral fibers travel through the trapezoid body
- From ACN to the Superior Olivary Complex either medial or lateral nucleus
- From SOC to Lateral Lemniscus
- Central nucleus of LL sends fibers to inferior colliculus
- Posterior nucleus receives fibers about intensity of sound from the Lateral superior olivary nucleus and goes to contralateral inferior colliculus
- From LL to Inferior colliculus
- From IC to MGN
- MGN to Primary auditory complex
Central deafness?
Ipsilateral deafness, can hear but can’t determine where it is coming from or what it is
Sensorineural deafness
- Damage to cochlea or cochlear nerve
- ispilateral deafness
Blood supply to the cochlear and auditory nuclei of pons and medulla?
Basilar artery
Blood supply to the inner ear and cochlear nuclei and what happens if it is occluded
- Internal auditory aka labyrinthine artery a branch off of AICA
- Occlusion results in monaural hearing loss can also damage facial nerve fibers and pontine gaze center
- cant look to side of lesion
Blood supply to the superior olivary complex and lateral lemniscus?
Short circumfrential branches of the Basilar artery
MGN blood supply?
Thalamogeniculate arteries
Inferior colliculus blood supply
Superior cerebellar and quadrigeminal arteries
Primary auditory cortex and assocaition cortices blood supply
Branches of M2
What hemisphere controls language?
- Dominant hemisphere typically on the left side
Brocas aphasia
- caused by occlusion of the frontal M4 branches
- difficulty turning thoughts into words and meniningful sounds, difficulty writing and no repetition
- Short phrases used
- Brocas Broken Speech
Wernickes aphasia
- occlusion of temporal and parietal M4 branches also hemorrhages into the thalamus
- Cannot comprehend speech or language
- Fluent paraphasic speech and no repetition
- happy babblers
What is the non dominant hemisphere responsible for?
- Non verbal communications such as
- tone of voice
- Prodosoy ( melodious intonation of speech)
- Emotion
- Area analogous to brocas
- Area analogous to werneikes
What is motor aprosodia
- Lesion in the area analogous to brocas resulting in the inability to convey emotion in your voice or prosody.
- Example was the teacher whose students couldn’t tell she was mad
What is Sensory aprosodia
- Inability to understand non verbal communication such as shoulder shrugs or sarcasm
- Lesion in the area analogous to wernikes
Describe the language pathway
- Begins in the primary auditory cortex to tell where sound is coming from
- Auditory assoc. cortex to classify the sound
- Wernikes area to understand
- Arcuate fasciculus to connect to brocas
- Brocas to instruct speech production
- Motor cortices to direct muscles to move
What is auditory agnosia?
- bilateral lesions to the anterior superior temporal lobes
- Person can hear the sound but they don’t know what it is and can’t describe it
Global aphasia?
- Occlusion of left ICA and M1 resulting in damage to werkines and brocas resulting in a complete loss of language
Conduction aphasia
- interruption to arcuate fasciculus
- Comprehension is normal
- Speech is fluent
- Patient cannot translate what someone says to them to formulate a correct response
- Repetition is not intact
Transcortical motor aphasia
- SImilar to brocas aphasia except repetition is intact
- caused by an anterior watershed infarct resulting in contralateral paresis and expressive language deficits
Transcortical sensory aphasia
- Similar to werkines except repetition is intact, much milder
- Posterior watershed infract of the MCA and PCA resulting in partial visual field deficits and receptive language deficit
