Hearing Flashcards
What is the law of specific nerve energies?
Muller - The neural pathway carrying the signal determines the sensation
What are the 2 theories of pitch reception?
- Place code theory (Helmholtz)
- Temporal code theory (Wever)
Describe the place code theory
- Specific pitch causes a specific place in the cochlear membrane to vibrate
- Specific auditory nerves carry the information code of the pitch
- Vibrations are of the same frequency with different oscillation sizes
What is the cochlear microphonic?
- small electrical signal that can be measured near hair cells
- Frequency of tones correlate to firing rate
What is the problem with the temporal code theory?
That while nerve firing rate can only go up to 1000Hz we can hear a range of 20-20000 Hz
What is the volley principle?
An idea stating that multiple neurons can provide a temporal code for frequency if each neuron fires at a distinct point in the period of a sound wave but does not fire on every period
Define interaural level difference (IAL)
The difference in level (intensity) between a sound arriving at one ear versus the other
Why is there a bigger difference in IAL for higher frequencies?
Because low frequencies are wider then the head and high frequencies have to vibrate through the head
What are the 2 ways of detecting azimuth?
interaural level difference and interaural time difference
What is the ‘cone of confusion’?
Regions in space where all sounds produce the same
time and level differences
What is the function of the pinnae?
Shape helps determine direction of sound
Name the 4 methods used to measure the distance of a sound
- Intensity
- Inverse-square law
- Spectral composition
- Direct vs reverberant energy
What are the 3 strategies used to segregate sound sources?
- Spatial separation
- Sound spectral/temporal qualities
- Auditory stream segregation (seperate auditory events)
Which theories of sound coding are most used for low vs high frequencies?
Place coding - high frequencies
Temporal coding - low frequencies
