Time-domain analysis of auditory-nerve-fiber firing rates

Abstract

Time-domain analysis of firing-rate data from over 200 fibers from the auditory nerve of cat has been used to estimate the formants of the synthetic-syllable stimuli. Distinct groups of fibers are identified based on intervals between peaks in the fiber firing rates. The large extent of some of these groups--over an octave in terms of characteristic frequency--and the lack of short intervals in the longer-interval groups suggest that the behavior of the nonlinear cochlear filters for these signals is effectively wideband with steep high-frequency cutoffs. The measured intervals within each group are very similar, and correspond to the period of the formant that dominates the group's response. These intervals are used to estimate the dynamic speech formants. The overall formant estimates are better than those of the previous spectral analyses of the neural data, and the details of lower-formant dynamics are tracked more precisely. The direct temporal representation of the formant in contrasted with the diffuse spectral representation, the dependence of spectral peaks on nonformant parameters, and the distortion of the spectrum by rectification. It is concluded that a time-domain analysis of the responses to complex stimuli can be an important addition to frequency-domain analysis for neural data, cochlear models, and machine processing of speech.

Correlation Factors Describing Primary and Spatial Sensations of Sound Fields

“…where coefficients a % À1Á64 and b % 2Á44: Calculated scale values s ASW by equation (13) and measured scale values are in good agreement (r ¼ 0Á97; p50Á01) [27]. These formulas also hold for complex noise [29].…”

“…Amplitudes of waves (I-IV) of the auditory brainstem response (ABR) reflect the sound pressure levels as a function of the horizontal angle of incidence to a listener [3]. Such neural activities, in turn, include sufficient information to attain the autocorrelation function (ACF), probably at the lateral lemniscus as indicated by F ll ðsÞ and F rr ðsÞ: In fact, the time domain analysis of firing rate from the auditory nerve of a cat reveals a pattern of ACF rather than the frequency domain analysis [13]. Pooled interspike interval distributions resemble the short time or the running ACF for low-frequency component.…”

Synchrony capture filterbank: Auditory-inspired signal processing for tracking individual frequency components in speech

“…Figure 1(a) shows peristimulus time histograms (PSTHs) for a five-formant synthetic vowel sound. 4 Sharp boundaries characteristic of synchrony capture are seen between the different CF regions driven by different dominant, formant-region harmonics of the multi-formant vowel. Note that in Fig.…”

Electrocochleographic documentation of temporal findings of speech perception in normal and hearing-impaired individuals

“…Physiologically, temporal information of sound stimuli in the cochlea is the temporal pattern of firings of each of the characteristic frequency fibers. Research in anesthetized animals has shown that the temporal patterns of firings of single fibers evoked by speech stimuli include information on the formant or formant transition of consonants [9,11,13]. However, spontaneous firing of single fibers during silence are unrecognized.…”