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How does the auditory nerve signal low-frequency sounds differently from high-frequency sounds?

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Meissner's corpuscle; mechanoreception — Mechanoreception In human skin, specialized nerve endings known as Meissner's corpuscles (or tactile corpuscles) are sensitive to touch. They are one of several different types of mechanoreceptors found in human skin.

The auditory system distinguishes between low- and high-frequency sounds primarily through the physical properties of the basilar membrane and the resulting neural activity sent to the brain.

Place Theory and Frequency Coding

According to the "place theory," different frequencies activate specific regions along the basilar membrane:
* High-frequency sounds cause the basal end of the membrane (near the oval window) to vibrate, as this area is stiffer and has less mass.
* Low-frequency sounds travel further along the membrane to vibrate the more flexible apical end at the tip of the cochlea.

The auditory nerve signals these frequencies based on which specific nerve fibers are activated by the hair cells in the most vigorously vibrating region. For high frequencies, this "place" information is the primary indicator of pitch.1

Temporal Coding

For low-frequency sounds (up to approximately 3,000 hertz), the auditory nerve also utilizes timing information. The nerve fibers fire at regularly recurring intervals that correspond to the phase of the sound wave, a process known as phase-locking. This allows the brain to interpret the timing of the stimulus as an additional indicator of pitch alongside the spatial location of the vibration.12