Central Auditory System Flashcards
(15 cards)
CN 7 and CN 8 travel via _______
internal acoustic meatus to the brainstem
Cochlear portion of CN 8 anatomical location
anterior-inferior
CN 7 facial nerve’s anatomical location
anterior-superior
Vestibular portion of CN 8 anatomical location
superior-inferior
What is the key to remembering the anatomical locations of CN 7 and CN 8 (cochlear)?
7-Up, Coke-down
*They both are anterior
CN 7 superior, CN 8 inferior
Describe how Type 1 and Type 2 nerve fibers descend from IE to the auditory nerve
- They become bundled and exit via the internal auditory meatus of the temporal bone.
- Bundled as spiral ganglion and will ascend to the brainstem to CN 8 (cochlear)
- They remain dedicated to either the vestibular or cochlear input that ascends from the cochlea via the auditory cortex
The tonotopical organization that begins in the cochlea is maintained throughout the ______
CANS
Cochlear Nucleus
The first synapses of CANS
located bilaterally and divided into the AVCN, PVCN, DCN
Location site for auditory brainstem implants
Receives information from the cochlea (ipsilaterally) and sends to the SOC
Superior Olivary Complex
The cochlear nuclei project to the bilateral SOC
Located in the caudal pons
Divided into the lateral and medial SOC
*takes info from the CN and begins to the process of interpreting and combing information
**sound localization via time diff and intensity b/t ears
Type 1 spiral ganglion neurons
primary neurons of the auditory pathway (IHC)
responsible for transmitting information from the cochlear hair cells to the brain
myelinated cell bodies
Type 2 spiral ganglion neurons
smaller subset
unmyelincated
innervated form the OHCs
transmit information form the OHC to the brain…helps with sound perception
Inferior Colliculus
midbrain structure that integrates the vast majority of ascending auditory info that projects via thalamus to the auditory cortex
works ipsilateral and contralateral
*relays point within the CANS as signals travel to the thalamus
formed with LF ipsilateral fibers and HF contralateral fibers
important for time duration for gap detection
Lateral lemniscus
located in the pons
contains two nuclei: ventral and dorsal
ventral (VNLL): sensitive to ITDs
dorstal (DNLL): sensitive to ILD and responsive to bilateral input
*receives bilateral and ipsilateral input from CN and SOC, then projects to the ipsilateral inferior colliculus
Medial geniculate body of the thalamus
located in the central part of the brain and projects off to the posterior end of the thalamus
three sections: ventral, dorsal, and medial (all sections output to the auditory cortex)
*responsible for the emotional response to auditory stimuli
**responsible for frequency discrimination, localization, the conditioned fear response, and rapid ordering of acoustic elements
Auditory cortex`
Completes advanced processing of auditory stimuli
responsible for speech understanding, language, and reading
