Entracking creates flat firing-rate profiles orthogonal to tonotopic organization.
Evidence
To some extent (increasingly so with increasing SPL), the representation hypothesized here is “orthogonal” to the tonotopic representation. The rate-place profile in the AN to a low-frequency tone increasingly broadens with increasing SPL, and flattens due to rate saturation (Kim and Molnar 1979 ). If a population of central neurons shows entracking, this property causes a stratification in the rate-place profile. Instead of a vertical or “hilly” profile where resolved components cause local increases in firing rate and unresolved components lead to a broad mound of activity, entracking generates horizontally flattened profiles or buttes, for which firing rate is dictated by the dominant interval between spikes fed to neurons in these frequency channels. For multiple, truly resolved components, a staircase of buttes would result with increasing firing rates corresponding to the frequency of successive harmonics. For unresolved components, many factors come into play (filter shape, limits to fine-structure and envelope, component phase), but buttes could be formed by neurons entracking to the dominant stimulus period. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4520
Categorization
Category: Definitional Content
- DEFINE: Defines ‘butte’ as the horizontal rate-plateau profile produced by entracking, contrasting with hilly tonotopic profiles.
Related
- Entracking generates horizontally flattened rate profiles that encode pitch as firing rate (similarity 0.93)
- Entracking neurons form plateau ‘buttes’ of uniform firing rate across a tonotopic profile (similarity 0.92)
- Entracking creates flat rate plateau codes that supplant tonotopic place codes (similarity 0.92)
- Brainstem entracking neurons fire one spike per stimulus cycle (similarity 0.84)
- Neurons can convert stimulus frequency directly into firing rate at the brainstem (similarity 0.82)
- Pitch can be coded by neuron firing rate matching the repetition frequency (similarity 0.81)
- Entracking firing rate rises linearly with tone frequency up to roughly 500 Hz (similarity 0.81)
- Entracking neurons keep firing rate clamped to stimulus frequency across SPLs (similarity 0.80)
- Entracking codes low-frequency pitch through uniform firing across neurons while high-frequency firing varies (similarity 0.80)
- Entracking emerges through multiple stages of convergent auditory inputs (similarity 0.79)
- Entracking firing rate stays level-invariant across a 20 dB dynamic range (similarity 0.78)
Broader Connections
- Groups of nerves firing in staggered cycles code frequencies above 300 Hz
#expands(0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 900