Response modulation of auditory-nerve fibers by am stimuli: effects of average intensity

Smith, Robert L.; Brachman, Michael L.

doi:10.1016/0378-5955(80)90034-9

Cited by 74 publications

(39 citation statements)

References 20 publications

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“…On the one hand, increase in SPL generates relatively fewer spikes that are consistently timed across presentations; on the other hand, the spikes of this reduced subset are timed more accurately. The first trend agrees with the loss of phase locking to the envelope with high sound levels (Smith and Brachman, 1980;Joris and Yin, 1992;Wang and Sachs, 1993), but an interpretation of both trends combined will require a detailed description of the mechanisms of spike generation.…”

Section: Effect Of Spl On Normalized Sacssupporting

confidence: 52%

Enhanced Temporal Response Properties of Anteroventral Cochlear Nucleus Neurons to Broadband Noise

Louage¹,

Heijden²,

Joris³

2005

J. Neurosci.

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Compared with auditory nerve (AN) fibers, trapezoid body (TB) fibers of the cat show enhanced synchronization to low-frequency tones. This phenomenon probably contributes to the high temporal resolution of binaural processing. We examined whether enhanced synchronization also occurs to sustained broadband noise. We recorded responses to a reference Gaussian noise and its polarity-inverted version in the TB of barbiturate-anesthetized cats. From these we constructed shuffled autocorrelograms (SACs) and quantified spike timing by measuring the amplitude and width of their central peak.Many TB fibers with low characteristic frequency (CF) showed SACs with higher and narrower central peaks than ever observed in the AN, indicating better consistency and precision of temporal coding. Larger peaks were also observed in TB fibers with high CF, but this was mostly caused by higher average firing rates, resulting in a larger number of coincident spikes across stimulus repetitions. The results document monaural preprocessing of the temporal information delivered to binaural nuclei in the olivary complex, which likely contributes to the high sensitivity to interaural time differences.

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Section: Effect Of Spl On Normalized Sacssupporting

confidence: 52%

Enhanced Temporal Response Properties of Anteroventral Cochlear Nucleus Neurons to Broadband Noise

Louage¹,

Heijden²,

Joris³

2005

J. Neurosci.

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“…As a result, the instantaneous rate of discharge of ANFs in response to low-frequency pure tones falls below the spontaneous rate (SR) during approximately every other half cycle (Johnson 1980), contrary to the idealized model used for motivating transposed tones. Second, phase locking to SAM tones degrades at a higher sound pressure level (SPL) arising from cochlear compressive nonlinearities (Joris and Yin 1992;Smith and Brachman 1980). Given the amplitude-modulated nature of transposed tones, a similar level dependency of phase locking may be expected.…”

Section: Introductionmentioning

confidence: 99%

Phase Locking of Auditory-Nerve Fibers to the Envelopes of High-Frequency Sounds: Implications for Sound Localization

Dreyer

Delgutte²

2006

Journal of Neurophysiology

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. Although listeners are sensitive to interaural time differences (ITDs) in the envelope of high-frequency sounds, both ITD discrimination performance and the extent of lateralization are poorer for high-frequency sinusoidally amplitudemodulated (SAM) tones than for low-frequency pure tones. Psychophysical studies have shown that ITD discrimination at high frequencies can be improved by using novel transposed-tone stimuli, formed by modulating a high-frequency carrier by a half-wave-rectified sinusoid. Transposed tones are designed to produce the same temporal discharge patterns in high-characteristic frequency (CF) neurons as occur in low-CF neurons for pure-tone stimuli. To directly test this hypothesis, we compared responses of auditory-nerve fibers in anesthetized cats to pure tones, SAM tones, and transposed tones. Phase locking was characterized using both the synchronization index and autocorrelograms. With both measures, phase locking was better for transposed tones than for SAM tones, consistent with the rationale for using transposed tones. However, phase locking to transposed tones and that to pure tones were comparable only when all three conditions were met: stimulus levels near thresholds, low modulation frequencies (Ͻ250 Hz), and low spontaneous discharge rates. In particular, phase locking to both SAM tones and transposed tones substantially degraded with increasing stimulus level, while remaining more stable for pure tones. These results suggest caution in assuming a close similarity between temporal patterns of peripheral activity produced by transposed tones and pure tones in both psychophysical studies and neurophysiological studies of central neurons.

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“…Because amplitude-and frequency-modulated (AM and FM) sounds are the building blocks of complex sounds, understanding how the auditory system encodes these signals has important practical and theoretical implications (Kay, 1982;Moore & Sek, 1992;Saberi, 1998). The peripheral mechanisms of AM encoding are relatively well understood, requiring a tracking of changes in firing rates of primary auditory afferents in response to the modulation envelope (Javel, 1980;Langner & Schreiner, 1988;Smith & Brachman, 1980). The mechanisms for coding FM signals are not as clear, because the FM envelope is flat.…”

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confidence: 99%

Detection of spatial cues in linear and logarithmic frequency-modulated sweeps

Hsieh

Saberi

2009

Attention, Perception & Psychophysics

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Frequency-and amplitude-modulated (FM and AM) sounds are the building blocks of complex sounds. In the present study, we investigated the ability of human observers to process spatial information in an important class of FM sounds: broadband directional sweeps common in natural communication signals such as speech. The stimuli consisted of linear or logarithmic unidirectional FM pulses that swept either up or down in frequency at various rates. Spatial localization thresholds monotonically improved as sweep duration decreased and as sweep rate increased, but no difference in performance was observed between logarithmic and linear or between upand down-frequency sweeps. Counterintuitive reversals in localization were observed which suggested that the localization of high-frequency sweeps may be strongly dominated by amplitude information even in situations in which one might consider timing cues to be critical. Implications of these findings for the localization of complex sounds are discussed.

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Response modulation of auditory-nerve fibers by am stimuli: effects of average intensity

Cited by 74 publications

References 20 publications

Enhanced Temporal Response Properties of Anteroventral Cochlear Nucleus Neurons to Broadband Noise

Enhanced Temporal Response Properties of Anteroventral Cochlear Nucleus Neurons to Broadband Noise

Phase Locking of Auditory-Nerve Fibers to the Envelopes of High-Frequency Sounds: Implications for Sound Localization

Detection of spatial cues in linear and logarithmic frequency-modulated sweeps

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