Zwicker tones arise centrally, not from cochlear mechanics or phase locking

Evidence

Here we assessed whether a musical pitch can be heard in the absence of phase locking, using Zwicker tones, ZTs (Zwicker 1964 ). A ZT is a faint, decaying tonal percept that can arise following the presentation of a notched broadband noise and that can last up to 5–6 s. The pitch is always within the frequency range of the notch, and depends on the level of the noise and the width of the notch. Several findings indicate that ZTs are unlikely to be produced mechanically at the level of the cochlea. Normally, no otoacoustic emissions (OAEs) were found at the frequency corresponding to the pitch of the ZT, except in the rare case when a subject had a spontaneous OAE which could be made temporarily audible by a preceding notched noise (without increasing its physical level), and no beating was observed between ZTs and a soft physical tone (Krump 1993 ). Also, while low frequency tones at moderate to high levels can affect the level of evoked OAEs, they did not affect the ZT (Wiegrebe et al. 1995 ). Thus, no mechanical activity correlated to the ZT exists in the cochlea, and there is unlikely to be phase locking to ZTs in the auditory periphery. — Dijk, Pim van, Physiology, Psychoacoustics and…, 5399

A ZT is a faint, decaying tonal percept that can arise following the presentation of a notched broadband noise and that can last up to 5–6 s. The pitch is always within the frequency range of the notch, and depends on the level of the noise and the width of the notch. … Several findings indicate that ZTs are unlikely to be produced mechanically at the level of the cochlea. Normally, no otoacoustic emissions (OAEs) were found at the frequency corresponding to the pitch of the ZT, except in the rare case when a subject had a spontaneous OAE which could be made temporarily audible by a preceding notched noise (without increasing its physical level), and no beating was observed between ZTs and a soft physical tone (Krump 1993 ). Also, while low frequency tones at moderate to high levels can affect the level of evoked OAEs, they did not affect the ZT (Wiegrebe et al. 1995 ). Thus, no mechanical activity correlated to the ZT exists in the cochlea, and there is unlikely to be phase locking to ZTs in the auditory periphery. The question addressed here is whether ZTs can evoke a musical pitch. — Dijk, Pim van, Physiology, Psychoacoustics and…, 5396

Several findings indicate that ZTs are unlikely to be produced mechanically at the level of the cochlea. Normally, no otoacoustic emissions (OAEs) were found at the frequency corresponding to the pitch of the ZT, except in the rare case when a subject had a spontaneous OAE which could be made temporarily audible by a preceding notched noise (without increasing its physical level), and no beating was observed between ZTs and a soft physical tone (Krump 1993 ). Also, while low frequency tones at moderate to high levels can affect the level of evoked OAEs, they did not affect the ZT (Wiegrebe et al. 1995 ). Thus, no mechanical activity correlated to the ZT exists in the cochlea, and there is unlikely to be phase locking to ZTs in the auditory periphery. — Dijk, Pim van, Physiology, Psychoacoustics and…, 5399

Categorization

• DEFINE: Defines what a Zwicker tone is and its key properties.
• SEED: The key experimental logic — a percept demonstrably free of peripheral mechanics can test whether pitch requires temporal codes — is a model of how to isolate a mechanism.
• SHARE: The OAE-beating and evoked-OAE evidence isolating ZTs to the neural stage is a tight experimental logic chain worth sharing with an auditory physiologist.
• corroborated: 4 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 5399; Dijk, Pim van, Physiology, Psychoacoustics and…, 5396
• XREF: connects to: Cubic difference tones arise inside the ear, not in the equipment — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3354; Zwicker tones have no cochlear mechanical or otoacoustic correlate. — Dijk, Pim van, Physiology, Psychoacoustics and…, 5396; Zwicker tones produce pitch without peripheral phase locking. — Dijk, Pim van, Physiology, Psychoacoustics and…, 5392 (+3 more)

Broader Connections

• Zwicker tones produce no correlate in cochlear mechanical activity #corroborates (0.95)
• Nonlinear cochlear mechanics make listeners perceive nonexistent difference tones #contradicts (0.85)
• The ear generates audible combination tones not present in the stimulus #contradicts (0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1571