Individual auditory nerve fibers cannot code the full hearing dynamic range
Evidence
Due to the saturation and limited dynamic ranges of individual fibers, an individual neuron cannot code the entire range of sound levels that are perceived by the human ear. The dynamic range (the range of levels between threshold and saturation) of an individual neuron is on the order of 20 to 40 dB and rarely exceeds 60 dB. Note that the dynamic range of human hearing is considered to be approximately 100 to 120 dB, suggesting that all three fiber types must be used to represent the entire dynamic range of hearing. Consider then that the high SR/low threshold fibers would be most involved in representing lowlevel stimuli, such as when auditory threshold is measured. On the other hand, high threshold/low SR fibers are most involved in auditory detection when a background noise is present. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 240
Categorization
- XREF: Directly connects to loss-of-compression and loudness-perception deficits in sensorineural hearing loss the reader tracks across chapters. — connects to: Single auditory neurons encode only a narrow 20-40 dB dynamic range — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 785; The cochlea cannot track dynamic intensity changes above roughly 1 kHz; Auditory nerve fibers of three spontaneous-rate types code different level ranges (+3 more)
- corroborated: 2 independent passages support this claim — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 240
Broader Connections
- Full hearing range requires pooling three auditory nerve fiber types
#expands(0.90) - Cochlear neuropathy harms supra-threshold encoding because noise targets high-threshold auditory fibers
#corroborates(0.80) — Dijk, Pim van, Physiology, Psychoacoustics and…, 5873 - The ear’s full dynamic range exists only near 4 kHz
#qualifies(0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 612