PSC1002/L24 Hearing & the Brain Flashcards
What happens when the outer hair cell amplifier is damaged? (3)
Fibre less sensitive
Affects speech intelligibility
Sounds more blurred and difficult to distinguish
How does place code (tonotopic organisation) encode sound frequency? (2)
Auditory system keeps track of where information originated on basilar membrane
Sound frequency mapped within processing centres and on surface of auditory complex
How does time code encode frequency? (2)
Firing of AP in auditory nerve fibres synchronise with peaks of sound waveform - phase locking
Time between AP encodes frequency of sound
For which frequencies of sound does time code occur?
Low frequencies
3-5kHz
Define phase locking.
Synchronisation of action potential firing to peaks in waveform of low frequency
What is a period and what is the reciprocal of this?
Period = time between AP
Reciprocal = frequency
What does the auditory nerve connect?
Cochlea to brain
What is the cochlea nucleus?
First synapse in auditory pathway
What is the function of the superior olivary complex?
Information from 2 ears interacts important for localising sound
Give another name for the inferior colliculus.
Midbrain auditory centre
Give another name for the medial geniculate body.
Thalamic auditory centre
Where is the auditory complex located?
In temporal lobe
How is sound localised? (2)
Horizontal plane - interaural differences in sound wave timing and intensity
Vertical plane - interactions of sound on pinna
What is the timing cue for all sounds?
Difference in sound onset time between two ears (except immediately in front or behind listener)
What is the timing cue for long, continuous sounds?
Difference in phase of sound between ears
