Cochlear liquid mass determines where each frequency penetrates the basilar membrane.
Evidence
The vibration enters the liquid through the oval window and travels at a very high speed in the duct. The round window acts as a sink for the vibration, and one might think that the vibration finds a route there by penetrating through the basilar membrane. This vibrating liquid column can be seen as a mass–spring system, and, as shown by Equation (2.6), the lower the mass, the higher the resonance frequency. High frequencies thus favour a shorter route, since the mass of the vibrating liquid decreases if the route is shorter. In contrast, the lowest frequencies favour a longer route, since the mass of the system is higher there. Added to this, the vibration favours penetrating the basilar membrane at a position where its frequency matches the characteristic frequency of the membrane. Thus, many different characteristics are optimized to make the frequency-to-place conversion of acoustic vibrations. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 749
Categorization
Category: Causal Relationships
- DEFINE: Explains the physical mechanism (mass-spring resonance) driving frequency-to-place conversion in the cochlea.
Related
- Cochlear pitch mapping exploits the mass of vibrating liquid varying with route length (similarity 0.91)
- The basilar membrane’s tapering shape enables it to sort sounds by frequency. (similarity 0.81)
- The ossicles convert air vibrations into mechanical movements that drive cochlear fluid (similarity 0.79)
- Resonance lowers impedance dramatically at an oscillator’s natural frequency (similarity 0.79)
- Tonotopic frequency ordering persists from cochlea to auditory cortex (similarity 0.78)
- Cochlear hydrodynamics can be simulated by analog electrical equivalent circuits (similarity 0.78)
- Just-noticeable frequency shifts map to constant basilar distances (similarity 0.78)