Neuroscience: Auditory System

inner hair cells

considered the primary auditory receptor cells

inner hair cells

purely afferent and are responsible only for the transmission of signals representing sound waves

sterocilia

protrusions from the inner and outer hair cells that convert physical force from sound into an electrical signal

glutamate

shearing of the sterocilia depolarizes the hair cells, which then releases an excitatory neurotransmitter called...

outer hair cells

receive efferent signals that have an important role for enhancing detection of low-intensity sounds

spiral ganglion

a group of neuron cell bodies in the cochlea whose axons create the cochlear portion of the VIII cranial nerve

peripheral auditory nervous system

includes the external, middle, and inner ears and cochlear nerve to the point where it communicates with the central nervous system

spiral ganglion

transmit nerve impulses from the cochlea to the cochlear nuclei in the brainstem

C-SLIMA
1. Cochlear Nuclei
2. Superior Olivary Complex
3. Lateral Lemniscus
4. Inferior Colliculus
5. Median Geniculate Nucleus
6. Primary Auditory Cortex

list the order of pathways in the Central Auditory Nervous System

medulla and pons

cochlear nuclei are located the junction between the __ and __

ipsilateral, contralateral

the axons from one cochlear nucleus project up to both the __ and __ superior olivary complex

Superior Olivary Complex

group of small auditory nuclei located in the pons of the brainstem

Superior Olivary Complex

the first component to receive binaural stimuli and functions in sound localization

lateral lemniscus

the ascending tract of axons from the SOC to the inferior colliculi

contralateral

majority of fibers carried through the lateral lemniscus are ___ (ipsilateral/contralateral)

inferior colliculi

located in the midbrain and receives input from the lateral lemniscus

medial geniculate nucleus (thalamus)

mainly, where do signals from the inferior colliculi project to?

inferior colliculus

functions mainly in binaural integration

true

T/F: more information from one ear is passed to the contralateral auditory cortex than to the ipsilateral cortex

inferior colliculus

in order for auditory information to be recognized as aspects of the same acoustic stimulus, they must be brought back together again which happens in the ___

medial geniculate nucleus

receives signals from the inferior colliculus and relays them to the auditory cortex

medial geniculate nucleus

appears to be a part of an arousal system - telling the brain to pay attention to what is going on in regards to sound

primary auditory cortex

located in the transverse temporal gyrus and receives signals from the medial geniculate nucleus

primary auditory cortex

closely interconnected with Wernicke's area, which is important for the comprehension of language

high-base
low-apex

in the cochlea, high frequency sounds are transduced at the __, and low frequency sounds are transduced at the ___

tonotopic organization

means that cells responsive to different frequencies are found in different places at each level of the central auditory system

characteristic frequency

the frequency at which individual hair cells and nerve cells are tuned to respond most effectively

true

T/F: each auditory neuron can respond to a broad band of frequencies, but each neuron has its own characteristic frequency

tonotopic organization

concept that explains why the physical organization of neurons in the ascending auditory nervous system by frequency extends from the cochlea to the auditory cortex

true

T/F: the spiral ganglion neurons are arranged tonotopically

tonotopy, phase locking

high frequencies are encoded by ___, but low frequencies are encoded by ___

tonotopy and phase locking

mid frequencies are encoded by a combination of...

false

T/F: Sound coming from one side will arrive at the ear on the opposite side earlier than at the same ear

true

T/F: Neural signals will arrive at the Rt. and Lt. superior olivary complexes at different times.

true

T/F: Sound intensity will be reduced when a sound
reaches the ear opposite from the sound source

false

T/F: The phase cycle of a sound when it arrives at each ear will be the same