Neurons can convert stimulus frequency directly into firing rate at the brainstem

Evidence

In the AN, ISI histograms of responses to low-frequency pure tones are always multimodal (Kiang et al. 1965 ); i.e., after firing a spike, fibers often skip one or more cycles before firing another spike. Cycle skipping allows temporal and average rate behavior to be uncoupled. For example, neither the sigmoidal shape of rate-level functions (firing rate as a function of stimulus SPL), their dynamic range, nor maximum firing rate, are dependent on stimulus frequency per se but on stimulus frequency relative to characteristic frequency (CF). … In contrast, in the CNS, skipping of cycles is often less prominent. At low stimulus frequencies, higher modes in the ISI distribution, at multiples of the stimulus period, can be strongly attenuated relative to the mode corresponding to the tone period … Perfect entracking means that a neuron fires one spike per cycle so that the firing rate equals the stimulus repetition frequency. … A rate-place profile for neurons with perfect entracking would look quite different from that in the AN, and stimulus frequency in an absolute sense would now affect the display. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4494

Categorization

Category: Causal Relationships

• DEFINE: Defines ‘entracking’ as firing one spike per cycle so rate equals stimulus frequency.

Related

• Brainstem entracking neurons fire one spike per stimulus cycle (similarity 0.93)
• Brainstem neurons can fire one spike per sound cycle, unlike auditory nerve fibers (similarity 0.93)
• Brainstem firing rate depends on absolute frequency, unlike the auditory nerve (similarity 0.89)
• Entracking neurons keep firing rate clamped to stimulus frequency across SPLs (similarity 0.88)
• Entracking firing rate rises linearly with tone frequency up to roughly 500 Hz (similarity 0.87)
• Entracking codes low-frequency pitch through uniform firing across neurons while high-frequency firing varies (similarity 0.85)
• Auditory nerve fibers skip cycles, uncoupling spike timing from firing rate (similarity 0.85)
• Pitch can be coded by neuron firing rate matching the repetition frequency (similarity 0.84)
• Entracking codes pitch through constant firing rate while spike phase stays irrelevant (similarity 0.84)
• Uniform cross-neuron firing rate distinguishes true entracking from mere low rate (similarity 0.84)
• Entracking firing rate stays level-invariant across a 20 dB dynamic range (similarity 0.83)
• Entracking creates flat firing-rate profiles orthogonal to tonotopic organization. (similarity 0.82)
• Periodicity entracking is distributed across brainstem structures, not localized in one center. (similarity 0.82)
• Entracking neurons form plateau ‘buttes’ of uniform firing rate across a tonotopic profile (similarity 0.82)
• Entracking generates horizontally flattened rate profiles that encode pitch as firing rate (similarity 0.82)