Discharge patterns of single fibers in the pigeon auditory nerve

Sachs, Murray B.; Young, Eric D.; Lewis, Richard

doi:10.1016/0006-8993(74)90253-4

Cited by 139 publications

(52 citation statements)

References 22 publications

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“…Phase-locking in fibres of the redwing blackbird is almost the same as in the cat (decreasing with frequency up to about 6 kHz; Sachs et al 1980a, b). Finally, tuning curves of single avian afferents are V-shaped, with selectivity (QIodB values) similar to comparable mammalian fibres (Manley and Leppelsack 1977;Sachs et al 1974).…”

Section: Introductionmentioning

confidence: 83%

“…In the cat, afferents have a mean spontaneous rate of 30 spikes s-1 (Sachs et al 1974). Both cat and guinea pig show a bimodal distribution of rates.…”

Section: Discussionmentioning

confidence: 99%

“…Neurophysiological investigations of auditorynerve units in birds have been carried out in pigeons, starlings and redwing blackbirds (Gross and Anderson 1976;Manley 1979Manley , 1980Manley and Gleich 1984;Manley and Leppelsack 1977;Sachs et al 1974Sachs et al , 1980a. From these studies several general conclusions emerged.…”

Section: Introductionmentioning

confidence: 99%

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Activity patterns of cochlear ganglion neurones in the starling

et al. 1985

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Summary. 1. Spontaneous activity and responses to simple tonal stimuli were studied in cochlear ganglion neurones of the starling.2. Both regular and irregular spontaneous activity were recorded (Figs. I to 5). Non-auditory cells have their origin in the macula lagenae. Mean spontaneous rate for auditory cells (all irregularly spiking) was 45 spikes s-1.3. In half the units having characteristic frequencies (CFs) <1.5 kHz, time-interval histograms (TIHs) of spontaneous activity showed regularly-spaced peaks or 'preferred' intervals. The spacing of the peak intervals was, on average, 15% greater than the CF-period interval of the respective units (Fig. 11).4. In TIH of lower-frequency cells without preferred intervals, the modal interval was also on average about 15% longer than the CF-period interval (Fig. 11). Apparently, the resting oscillation frequency of these cells lies below their CF.5. Tuning curves (TCs) of neurones to short tone bursts show no systematic asymmetry as in mammals. Below CF 1 kHz, the low-frequency flanks of the TCs are, on average, steeper than the high-frequency flanks. Above CF 1 kHz, the reverse is true (Fig. 15).6. The cochlear ganglion and nerve are tonotopically organized. Low-frequency fibres arise apically in the papilla basilaris and are found near non-auditory (lagenar) fibres (Figs. 2 and 19).7. Discharge rates to short tones were monotonically related to sound presure level (Fig. 20). Saturation rates often exceeded 300 spikes s-1.8. 'On-off' responses and primary suppression of spontaneous activity were observed (Figs. 22 and 23).Abbreviations." CF characteristic frequency; TC tuning curve; TIH time interval histogram 9. A direct comparison of spontaneous activity and tuning-curve symmetry (Fig. 15b) revealed that, apart from quantative differences, fundamental qualitative differences exist between starling and guinea-pig primary afferents.

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Section: Introductionmentioning

confidence: 83%

“…In the cat, afferents have a mean spontaneous rate of 30 spikes s-1 (Sachs et al 1974). Both cat and guinea pig show a bimodal distribution of rates.…”

Section: Discussionmentioning

confidence: 99%

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Activity patterns of cochlear ganglion neurones in the starling

et al. 1985

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“…The ability of these models to predict IC responses in the budgerigar highlights an emerging pattern of broad similarities in auditory function between birds and mammals up to at least the level of the auditory midbrain (Ryugo and Parks 2003;Woolley and Portfors 2013). While birds and mammals exhibit differences in the anatomy of the cochlea related to extension of the upper frequency limit of hearing in mammals (Manley 2010), auditory nerve fibers in both groups show similar ranges of spontaneous activity, minimum thresholds for tone stimuli, frequency tuning bandwidth as a function of BF, and dynamic range/rate saturation (Sachs et al 1974;Manley et al 1985). Furthermore, auditory nerve fibers in birds, as in mammals, encode AM through envelope synchrony and not through changes in average discharge rate with modulation depth (Gleich and Klump 1995).…”

Section: Discussionmentioning

confidence: 99%

Midbrain Synchrony to Envelope Structure Supports Behavioral Sensitivity to Single-Formant Vowel-Like Sounds in Noise

Henry

Abrams

Forst

et al. 2016

JARO

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Vowels make a strong contribution to speech perception under natural conditions. Vowels are encoded in the auditory nerve primarily through neural synchrony to temporal fine structure and to envelope fluctuations rather than through average discharge rate. Neural synchrony is thought to contribute less to vowel coding in central auditory nuclei, consistent with more limited synchronization to fine structure and the emergence of average-rate coding of envelope fluctuations. However, this hypothesis is largely unexplored, especially in background noise. The present study examined coding mechanisms at the level of the midbrain that support behavioral sensitivity to simple vowel-like sounds using neurophysiological recordings and matched behavioral experiments in the budgerigar. Stimuli were harmonic tone complexes with energy concentrated at one spectral peak, or formant frequency, presented in quiet and in noise. Behavioral thresholds for formant-frequency discrimination decreased with increasing amplitude of stimulus envelope fluctuations, increased in noise, and were similar between budgerigars and humans. Multiunit recordings in awake birds showed that the midbrain encodes vowel-like sounds both through response synchrony to envelope structure and through average rate. Whereas neural discrimination thresholds based on either coding scheme were sufficient to support behavioral thresholds in quiet, only synchrony-based neural thresholds could account for behavioral thresholds in background noise. These results reveal an incomplete transformation to average-rate coding of vowel-like sounds in the midbrain. Model simulations suggest that this transformation emerges due to modulation tuning, which is shared between birds and mammals. Furthermore, the results underscore the behavioral relevance of envelope synchrony in the midbrain for detection of small differences in vowel formant frequency under real-world listening conditions.

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“…PSTH peaks were separated in time by intervals equal to the inverse of the neuron's best frequency (BF), a 2π phase interval. Individual spike timing varied, consistent with phase locking (Anderson et al 1970;Sachs et al 1974;Joris et al 1994;Köppl 1997). For each intracellular recording, we quantified the temporal distance between the PSTH peaks.…”

Section: Multiples Of 2πmentioning

confidence: 99%

The Role of Conduction Delay in Creating Sensitivity to Interaural Time Differences

Carr

Ashida

Wagner

et al. 2016

Advances in Experimental Medicine and Biology

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Axons from the nucleus magnocellularis (NM) and their targets in nucleus laminaris (NL) form the circuit responsible for encoding interaural time difference (ITD). In barn owls, NL receives bilateral inputs from NM, such that axons from the ipsilateral NM enter NL dorsally, while contralateral axons enter from the ventral side. These afferents act as delay lines to create maps of ITD in NL. Since delay-line inputs are characterized by a precise latency to auditory stimulation, but the postsynaptic coincidence detectors respond to ongoing phase difference, we asked whether the latencies of a local group of axons were identical, or varied by multiples of the inverse of the frequency they respond to, i.e., to multiples of 2π phase. Intracellular recordings from NM axons were used to measure delay-line latencies in NL. Systematic shifts in conduction delay within NL accounted for the maps of ITD, but recorded latencies of individual inputs at nearby locations could vary by 2π or 4π. Therefore microsecond precision is achieved through sensitivity to phase delays, rather than absolute latencies. We propose that the auditory system "coarsely" matches ipsilateral and contralateral latencies using physical delay lines, so that inputs arrive at NL at about the same time, and then "finely" matches latency modulo 2π to achieve microsecond ITD precision.

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Discharge patterns of single fibers in the pigeon auditory nerve

Cited by 139 publications

References 22 publications

Activity patterns of cochlear ganglion neurones in the starling

Activity patterns of cochlear ganglion neurones in the starling

Midbrain Synchrony to Envelope Structure Supports Behavioral Sensitivity to Single-Formant Vowel-Like Sounds in Noise

The Role of Conduction Delay in Creating Sensitivity to Interaural Time Differences

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