Week 4 Flashcards
Anatomy of the central auditory mechanism
Consist of all brain structures that contribute to the transmission and processing of auditory signals coming from the cochlear via auditory nerve
Anatomy of the central auditory mechanisms consist of
Brain stem structures(cochlear nuclei, ascending/descending auditory pathways, superior olivary nucleus, trapezoid body, lateral lemniscus)
Thalamic structures(medial geniculaye body/nucleus)
Cerebral structures(area 41, 42, 22, and 21)
The cochlear nerve
Made up of the individual receptor nerve fibers that connect with hair cells
Consists of 2 types of fibers
Type 1 (myelinated)
Type 2 (unmyelinated and myelinated)
Type 1 fibers
Connect with and receive input from the inner hair cells
Carry information about the moment to moment variations in the frequency of a sound
Type 2 fibers
The unmyelinated fibers connect with the outer hair cells
Carry information about the intensity of sound over a wide dynamic range
The cochlear nuclei
Unmyelinated axons from outer hair cells connect on the ventral cochlear nucleus
The myelinated fibers connect onto the dorsal nuclei
Functions of the ventral cochlear nucleus
Contributes to sound localization
Encodes a spectrum of sounds
Functions of the dorsal cochlear nucleus
Contributes to sound localization
Superior olivary nucleus
Located in the pons
Compares input from the right and left hemisphere cochlear nuclei
Consist of medial and superior olivary nuclei
Lateral superior olive
First location to detect interaural intensity differences
Responds more strongly to ipsilateral sounds
Lateral lemniscus
Exerts inhibitory control over the inferior colliculi of both sides during sound localization functions
Inferior colliculus
Site where most auditory input converges and is integrated
This is where information from the MSO and LSO is integrated to precisely pinpoint the sound source
Medial geniculate body
Majority of auditory fibers go to the medial geniculate body of the thalamus
