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
This area is responsible for instruction for language output, planning the movements to produce speech, and providing grammatical function of words. Important for word production and grammar.
Broca’s
The right hemisphere (non-dominant) has what two areas?
Area Analogous to Wernicke’s area
Area Analogous to Broca’s area
This area is responsible for interpreting nonverbal signals from other people (i.e., body language).
Area Analogous to Wernicke’s area
This area is responsible for providing instructions for producing non-verbal communication including emotional gestures and intonation of speech.
Area Analogous to Broca’s area
What happens if there is damage to one of the areas in the right hemisphere (non-dominant)?
It can cause people to be very literal (can’t understand sarcasm).
This is what links Wernicke’s and Broca’s areas.
Arcuate Fasciculations
Explain the general pathway for language.
Primary Auditory Cortex –
Auditory Association Cortex –
Wernicke’s Area –
Subcortical Connections (Arcuate Fasciculations) –
Broca’s Area –
Oral and throat region of Sensorimotor Cortex
Explain what happens at each step in the pathway for language.
Auditory discrimination –
Classification of sounds (language vs. other sounds) –
Auditory comprehension, vocabulary –
Link Wernicke’s and Broca’s areas –
Instructions for language output –
Cortical output to speech muscles
What is being tested when a patient is asked to say “No if’s and’s or but’s”?
1) Testing ability to repeat (Arcuate Fasciculus)
2) Testing grammar/syntax (Broca’s)
What are all the actions of Broca’s area?
Word processing
Grammar (syntax)
Word production
Articulation
What are all the actions of the Lateral Temporal Cortex?
Semantic knowledge (understanding the meaning of a sentence)
Word recognition (meaning)
What are all the actions of Wernicke’s area?
Word representation
Word retrieval
This is the term for the inability to identify an object despite being able to perceive it.
Agnosia
This is the inability to describe a sound that has been heard, for example a person could hear a fire alarm going off but not know that it is the fire alarm.
Auditory Agnosia
How is Auditory Agnosia caused?
A bilateral lesion to the unimodal (primary) sensory association cortex
***This is incredibly rare since it’s bilateral. A person may have had a stroke on one side then damage to the other side to have this occur.
Wernicke’s aphasia, also called ________ or ________ aphasia, is a defect of the comprehension of language. Expression is fine.
Receptive
Fluent
***Fluent just means words can come out fluently, but don’t make sense
What are the symptoms of Wernicke’s aphasia?
Unable to understand what is said to them
Unable to read (alexia)
Unable to write comprehensible language (agraphia)
Display fluent paraphasic speech (word salad)
T/F. For Wernicke’s aphasia, patients are generally not aware they have a problem or don’t understand what is happening. This keeps them from getting frustrated or depressed about it. Broca’s aphasia patients however, do understand what is happening and get very frustrated and depressed because they can’t speak correctly.
True
Broca’s aphasia, also called __________ or _________ aphasia, is the loss of the ability to speak fluently. Patients can understand spoken and written language.
Expressive
Non-fluent
Most severe forms of Broca’s aphasia result in…
Mutism (inability to speak at all)
Less severe forms of Broca’s aphasia result in short habitual phrases like “hi” or “thank you”, speech is slow and labored with poor enunciation, and nonessential words are omitted (telegraphic speech). Writing also often has _________ mistakes.
Grammar
In this type of aphasia, there is a lesion of the Lateral Sulcus. This hits both Wernicke’s and Broca’s, resulting in receptive and expressive deficits. Reading and writing is also impaired.
Global aphasia
***Don’t understand what is being said to them AND can’t express anything
Global aphasia is a type of non-fluent aphasia and is often the result of a…
Massive stroke
This type of aphasia is similar to Broca’s aphasia, except a person has preserved grammar understanding.
Transcortical Motor aphasia
This type of aphasia is similar to Wernicke’s aphasia, except a person can repeat words back.
Transcortical Sensory aphasia
This is a type of fluent aphasia that is due to a lesion of the Supramarginal Gyrus and Arcuate Fasciculus. Patients are unable to repeat, but have intact fluency, good comprehension, and intact reading. Speech is interrupted by word-finding difficulties, and writing is impaired.
Conduction aphasia
What type of aphasia is being described below?
- Nonfluent
- Impaired grammar
- Comprehension impaired for complex sentences
- Naming preserved
- Repetition impaired for complex sentences
Broca’s aphasia
What is the location of the lesion for Broca’s aphasia?
Left inferior frontal gyrus (Broca area and surroundings)
What type of aphasia is being described below?
- Fluent
- Grammar may be normal
- Comprehension impaired for single words
- Naming impaired
- Repetition impaired for single words
Wernicke’s aphasia
What is the location of the lesion for Wernicke’s aphasia?
Left superior temporal gyrus, inferior parietal lobule, posterior middle temporal gyrus
What type of aphasia is being described below?
- Fluent
- Grammar preserved
- Comprehension normal
- Naming preserved
- Repetition impaired
Conduction aphasia
What is the location of the lesion for Conduction aphasia?
Arcuate Fasciculus
What type of aphasia is being described below?
- Nonfluent
- Grammar preserved
- Comprehension normal
- Naming preserved
- Repetition preserved
Transcortical Motor aphasia
***Remember, this is like Broca’s aphasia except it has preserved grammar!
What is the location of the lesion for Transcortical Motor aphasia?
ACA-MCA border zone infarction
What type of aphasia is being described below?
- Fluent
- Grammar preserved
- Comprehension impaired
- Naming impaired
- Repetition preserved
Transcortical Sensory aphasia
***Remember, this is like Wernicke’s aphasia except it has preserved repetition!
What is the location of the lesion for Transcortical Sensory aphasia?
MCA-PCA border zone infarction
This type of aphasia causes word-finding difficulties, but everything else is normal.
Anomic aphasia
T/F. There can be mixed transcortical aphasia, involving both motor and sensory.
True
