Cochlear impulse responses resolved into sets of gammatones: the case for beating of closely spaced local resonances

Bell, Andrew; Wit, H. P.

doi:10.7717/peerj.6016

Cited by 6 publications

(2 citation statements)

References 70 publications

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“…In this way, a keyboard of 1.06 steps might arise, generating something akin to the 'spiral staircase' in the cochlea that has been described by Shera on the basis of his detailed otoacoustic measurements [9]. There is also recent further evidence that multiple, discrete resonating elements might exist in the mammalian cochlea, each with a step size of about 1.1 [31]. However, rather than being fixed in place, it is possible that the steps might, in line with Demany's suggestion, be dynamic, synchronising automatically to incoming tones and able to register shifts of frequency -melodies -in terms of relative semitone steps.…”

Section: Data and Modelmentioning

confidence: 96%

A Natural Theory of Music Based on Micromechanical Resonances Between Cochlear Sensing Cells

Bell¹

2019

J Hear Sci

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The origins of music remain obscure. Here it is pointed out that the outer hair cells in the cochlea lie approximately in a regular, hexagonal array, so it appears significant that important musical ratios -in particular the semitone, octave, perfect fifth, and major third -appear in the relative distances between adjacent cells. The speculation made here is that if the intercell distances are inherently tuned in this way, then incoming sound could initiate reverberating activity between the cells, and a musical ratio could be signaled by simultaneous standing waves in one cell-cell distance and in another which adjoins it. Essentially, the spacings between the cells might correspond to the lengths of miniature, musically tuned cavities.This speculative model of cell-cell interaction can explain recent observations that the human cochlea spontaneously emits low-level sound at intervals close to a semitone, and that the hearing thresholds of some subjects exhibit a whole "keyboard" of semitone-like intervals. These recent findings are striking, and appear more than coincidence. They prompt the key question, why? A possible answer may lie, it is suggested, with the distinct 2-dimensional geometry of the outer hair cells in the plane of the basilar membrane, which commonly exhibits a 19° alignment. This angle corresponds to a relative distance of 1.06, which is close to a semitone. It is pointed out that the same geometry which generates a natural semitone also produces other musically significant ratios. Perhaps, then, music might be an innate property of the human auditory system -and hence that there might be a natural basis for preferred musical intervals.Natural theories have often been criticised, with some saying that music is a learned faculty and depends only on culture. However, evidence has accumulated that there do seem to be musical universals, and therefore that music might indeed have a natural basis, most commonly thought to be via some neural processing in the brain. The explanatory model put forward here as the basis for further exploration suggests that musical analysis might actually begin in the periphery -in the cochlea itself.

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Section: Data and Modelmentioning

confidence: 96%

A Natural Theory of Music Based on Micromechanical Resonances Between Cochlear Sensing Cells

Bell¹

2019

J Hear Sci

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“…The idea, elaborated below, is that each row of outer hair cells could, if it acted in antiphase to its neighbouring rows, set up a series of nodes and antinodes which would then act as the "interdigital fingers" of an active surface acoustic wave (SAW) resonator inside the cochlea (13). Finally, a recent paper (14) finds that cochlear impulse responses seem to be built up from multiple resonating elements, a result directly supporting the resonance picture.…”

Section: Introductionmentioning

confidence: 95%

New Perspectives on Old Ideas in Hearing Science: Intralabyrinthine Pressure, Tenotomy, and Resonance

Bell¹

2018

J Hear Sci

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It is natural to think that hearing science progresses linearly, making new discoveries and opening up fresh vistas. But it doesn't always happen that way, and false starts are not uncommon. Here a brief survey is made of ideas about the mechanics of the middle ear and cochlea that appeared before 1900 but which have now, after a period of neglect, attracted renewed attention. Luminaries of 19th-century otology -Helmholtz and Weber-Liel -are used to illustrate the case. Three of their ideas -the mode of action of the middle ear muscles, the role of intralabyrinthine pressure, and resonance in the cochlea -were central to their thinking but for various reasons were later set aside. Notably, however, some old perspectives -such as the value of tenotomy in Meniere's disease -appear consistent with recent suggestions. Another discovery of modern science -Piezo1, a piezoelectric channel protein shaped like a propeller -strengthens the idea that pressure-sensing is crucial to cochlear function and indeed that Helmholtz's original resonance theory might still have merit.

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Information Processing by Onset Neurons in the Cat Auditory Brainstem

Recio-Spinoso

Rhode

2020

JARO

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Octopus cells in the ventral cochlear nucleus (VCN) have been difficult to study because of the very features that distinguish them from other VCN neurons. We performed in vivo recordings in cats on well-isolated units, some of which were intracellularly labeled and histologically reconstructed. We found that responses to low-frequency tones with frequencies G 1 kHz reveal higher levels of neural synchrony and entrainment to the stimulus than the auditory nerve. In responses to higher frequency tones, the neural discharges occur mostly near the stimulus onset. These neurons also respond in a unique way to 100 % amplitude-modulated (AM) tones with discharges exhibiting a bandpass tuning. Responses to frequency-modulated sounds (FM) are unusual: Octopus cells react more vigorously during the ascending than the descending parts of the FM stimulus. We examined responses of neurons in the ventral nucleus of the lateral lemniscus (VNLL) whose discharges to tones and AM sounds are similar to octopus cells. Repeated stimulation with short tone pips of VCN and VNLL onset neurons evokes trains of action potentials with gradual shifts toward later times in their first spike latency. This behavior parallels short-term post-synaptic depression observed by other authors in in vitro VCN recordings of octopus cells. VCN and VNLL onset units in cats respond to frozen noise stimuli with gaps as narrow as 1 ms with a robust discharge near the stimulus onset following the gap. This finding suggests that VCN and VNLL onset cells play a role in gap detection, which is of great importance to speech perception.

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Cochlear impulse responses resolved into sets of gammatones: the case for beating of closely spaced local resonances

Cited by 6 publications

References 70 publications

A Natural Theory of Music Based on Micromechanical Resonances Between Cochlear Sensing Cells

A Natural Theory of Music Based on Micromechanical Resonances Between Cochlear Sensing Cells

New Perspectives on Old Ideas in Hearing Science: Intralabyrinthine Pressure, Tenotomy, and Resonance

Information Processing by Onset Neurons in the Cat Auditory Brainstem

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