Spatiotemporal Representation of the Pitch of Harmonic Complex Tones in the Auditory Nerve

Abstract

The pitch of harmonic complex tones plays an important role in speech and music perception and the analysis of auditory scenes, yet traditional rate-place and temporal models for pitch processing provide only an incomplete description of the psychophysical data. To test physiologically a model based on spatiotemporal pitch cues created by the cochlear traveling wave (Shamma, 1985), we recorded from single fibers in the auditory nerve of anesthetized cat in response to harmonic complex tones with missing fundamentals and equalamplitude harmonics. We used the principle of scaling invariance in cochlear mechanics to infer the spatiotemporal response pattern to a given stimulus from a series of measurements made in a single fiber as a function of fundamental frequency F 0 . We found that spatiotemporal cues to resolved harmonics are available for F 0 values between 350 and 1100 Hz and that these cues are more robust than traditional rate-place cues at high stimulus levels. The lower F 0 limit is determined by the limited frequency selectivity of the cochlea, whereas the upper limit is caused by the degradation of phase locking to the stimulus fine structure at high frequencies. The spatiotemporal representation is consistent with the upper F 0 limit to the perception of the pitch of complex tones with a missing fundamental, and its effectiveness does not depend on the relative phase between resolved harmonics. The spatiotemporal representation is thus consistent with key trends in human psychophysics.

Triagem da Afinação Vocal: comparação do desempenho de musicistas e não musicistas

“…When comparing isolate tone tasks with tone sequencing, both groups had more right matches at the isolate tone task and, for the NMG, the sequencing task turned out to be more difficult ( Table 3), showing that it seems that musical learning, either formal or informal, helps the individual to overcome this greater difficulty that is the sound sequencing (13)(14)(15)(16)(17) . This fact corroborates the study that concluded that the longer the sequence of auditory stimuli for the sequencing task, the more difficult the activity becomes, since it involves a greater number of auditory abilities (12) and a greater auditory processing refinement (21) . Many people that do not sing in tune process musical information correctly, however they are unable to produce a desired tone.…”

“…The administration procedure of the Pitch-matching Scanning included the discrimination and vocal reproduction of isolate tones and the temporal ordination of some tones, always by means of dichotic listening. This procedure involves the physiologic mechanism of discrimination of sound patterns related to the temporal ordination abilities (non-verbal gnostic process) (12) . Musicians had more right matches for isolate tones than non-musicians (Table 1).…”

“…During the task that involved the reproduction of a sound sequencing of frequency patterns, musicians also showed a better performance when compared to non-musicians (Table 2). Since every sound sequence perception involves more auditory abilities, if compared to isolate tone perception, individuals usually present better performance for simpler tasks as they demand less from central capabilities (12) . It is known that musical experience enhance auditory perception, both of duration and frequency, given that musicians are superior to non-musicians (18)(19)(20) .…”

Understanding How Neural Circuits Measure Pitch

“…One attractive alternate model uses a synergistic approach, relying on the spatial pattern of temporal information (Shamma, 1985). Recently, Cedolin and Delgutte (2010) provided the first physiological evidence that spatiotemporal information from auditory nerve responses can be used to extract pitch.…”

“…To test the spatiotemporal pitch model, Cedolin and Delgutte (2010) recorded singleunit responses to harmonic complex tones from the auditory nerve of anesthetized cats. Given the difficulty in finely sampling neighboring auditory nerve fibers with single-unit recordings, Cedolin and Delgutte (2010) instead used the property of scaling invariance, where local spatiotemporal response patterns can be inferred from the response of a single auditory nerve fiber.…”