Central Auditory Processing Flashcards
(43 cards)
What is the Central Auditory Nervous system responsible for?
What is its mode of operation?
- Information Processing
- Electrochemical
State the five functions an auditory system has to do.
For each of them, state which part of the central auditory system is responsible.
- Detect sounds (sensitivity) –> Auditory Nerve
- Discriminate between sounds (selectivity) –> Auditory Nerve
- Determine source position –> Midbrain (brainstem)
- Group & segregate sounds –> Cortex
- Interpret sounds –> Cortex
What does selectivity (discrimination between sounds) allow you to do?
- Distinguish & focus on one sound in a noisy environment
(e. g. listen to one person)
Briefly outline the central auditory pathway.
- Cochlear Nuclei
- Auditory Nerve
- Superior Olivary Complex
- Lateral Lemniscus
- Inferior Colliculus
- Medial Geniculate Body
- Auditory Cortex

How many Inner Hair Cells (IHCs) does a Type I Fibre contact with?
- One

What do each Inner Hair Cells (IHC) synapse onto?
- Many (around 10) Auditory Nerve Fibres (ANFs)
(1 to many)

What are the two types of hair cells?
- Inner Hair Cell
- Outer Hair Cell
What do OHCs synapse onto?
- Lots of OHCs synapse onto one auditory nerve fibre
(many-to-one mapping)

What happens when a sound of a particular frequency is fed into the ear?
- Movement of the basilar membrane takes place at a particular point
- Hair cells respond to this sound
What type of frequencies do hair cells close to the base (outside bit) respond to?
- High Frequency
What type of frequencies do hair cells close to the apex (centre) respond to?
- Low Frequency
What is tonotopy?
- Map of frequency
- Adjacent cells will respond to similar frequencies
Other than in the basilar membrane, what other place is tonotopy seen?
- Auditory Nerve Fibres (preserved)
What type of Auditory Nerve Fibre do Outer Hair Cells (OHCs) synapse onto?
- Type 2 ANFs
What type of Auditory Nerve Fibre do Inner Hair Cells (IHCs) synapse onto?
- Type 1 ANFs
What type of cell is an ANF?
Where does its cell body reside?
- Bipolar Cell
- Cell Body –> in the Spiral Ganglion
What percentage of ANFs synapse with IHCs?
- 95%
(of the roughly 30,000 ANFs)
Roughly how any Type I fibres synapse onto a single IHC?
- Average is 10
- Up to 20
How many IHCs does a single Type I Fibre synapse with?
- One
What do Type I Fibres do?
- Afferent Fibres
- Transmit information from the cochlea to the CNS
Briefly, what is the role of an IHC & OHC?
- IHC –> responsible for hearing sound
- OHC –> responsible for amplifying sound
Collectively, what are ANFs called when they leave the cochlea?
- ANFs Congregate
- Join the Vestibular Apparatus
- Make up the Vestibulo-Cochlear Nerve

Where do efferent fibres to the cochlea come from?
- Superior Olives in the Brainstem

What does an increase in 10 dB mean in real terms?
- 10x increase in power





