How Internally Coupled Ears Generate Temporal and Amplitude Cues for Sound Localization

Vedurmudi, Anupam Prasad; Goulet, Julie; Christensen‐Dalsgaard, Jakob; Young, Bruce A.; Williams, Ross; Hemmen, J. Leo van

doi:10.1103/physrevlett.116.028101

Cited by 39 publications

(94 citation statements)

References 14 publications

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“…Model simulations for internally coupled ears in vertebrates [36,37] have shown a similar functionality of internally connected ears, where coupling may enhance amplitude differences in the high-frequency range. We found that for the field cricket, directional sensitivity was not limited to the calling song frequency, but was rather broadly tuned, similar to observations in a tree cricket [33].…”

Section: Discussionmentioning

confidence: 99%

Frequency tuning and directional sensitivity of tympanal vibrations in the field cricketGryllus bimaculatus

Lankheet

Cerkvenik

Larsen

et al. 2017

J. R. Soc. Interface.

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Female field crickets use phonotaxis to locate males by their calling song. Male song production and female behavioural sensitivity form a pair of matched frequency filters, which in Gryllus bimaculatus are tuned to a frequency of about 4.7 kHz. Directional sensitivity is supported by an elaborate system of acoustic tracheae, which make the ears function as pressure difference receivers. As a result, phase differences between left and right sound inputs are transformed into vibration amplitude differences. Here we critically tested the hypothesis that acoustic properties of internal transmissions play a major role in tuning directional sensitivity to the calling song frequency, by measuring tympanal vibrations as a function of sound direction and frequency. Rather than sharp frequency tuning of directional sensitivity corresponding to the calling song, we found broad frequency tuning, with optima shifted to higher frequencies. These findings agree with predictions from a vector summation model for combining external and internal sounds. We show that the model provides robust directional sensitivity that is, however, broadly tuned with an optimum well above the calling song frequency. We therefore advocate that additional filtering, e.g. at a higher (neuronal) level, significantly contributes to frequency tuning of directional sensitivity.

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Section: Discussionmentioning

confidence: 99%

Frequency tuning and directional sensitivity of tympanal vibrations in the field cricketGryllus bimaculatus

Lankheet

Cerkvenik

Larsen

et al. 2017

J. R. Soc. Interface.

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“…As in any linear system with a periodic input, one can introduce impedances, complex numbers, as fit parameters but that is not an a-priori theory based on geometry and tympanic elasticity only. Based on the 2- and 3-dimensional wave equation that describe waves in the 3-dimensional air-filled cavity and with damping, which is important, in the 2-dimensional eardrums, Vossen et al (2010) and Vedurmudi et al (2016a) were the first to present a complete mathematical theory, the former focusing on lizards and the latter encompassing the characteristics of all terrestrial vertebrates with ICE. It turns out that the 3-dimensional geometry plays a remarkable, unforeseen, role; for details including the key role played by the tympanic fundamental frequency, we refer to Vedurmudi et al (2016b).…”

Section: Intermezzomentioning

confidence: 99%

Animals and ICE: meaning, origin, and diversity

Hemmen

Christensen‐Dalsgaard

Carr

et al. 2016

Biol Cybern

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ICE stands for internally coupled ears. More than half of the terrestrial vertebrates, such as frogs, lizards, and birds, as well as many insects are equipped with ICE, that utilize an air-filled cavity connecting the two eardrums. Its effect is pronounced and two-fold. On the basis of a solid experimental and mathematical foundation it is known that there is a low-frequency regime where the internal time difference (iTD) as perceived by the animal may well be 2-5 times higher than the external ITD, the interaural time difference, and that there is a frequency plateau over which the fraction iTD/ITD is constant. There is also a high-frequency regime where the internal level (amplitude) difference iLD as perceived by the animal is much higher than the interaural level difference ILD measured externally between the two ears. The fundamental tympanic frequency segregates the two regimes. The present special issue provides an overview of many aspects of ICE, be they acoustic, anatomical, auditory, mathematical, or neurobiological. A focus is on the hotly debated topic of what aspects of ICE animals actually exploit neuronally to localize a sound source.

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“…Small creatures such as flies and lizards are known to possess the capability of accurately sensing the angle of an incident sound wave whose wavelength is much larger than their physical dimensions. Such an exotic characteristic in these small creatures has inspired miniature directional sensors both in optics and acoustics . The mechanisms behind the subwavelength directional sensing are explained with coupled resonances that amplify acoustic energy stored in each resonance.…”

Section: Introductionmentioning

confidence: 99%

“…For example, miniature MEMS directional sound sensors mimic the Ormia ochracea fly's hearing system where two eardrums of the fly are mechanically coupled, supporting dual vibration modes sensitive to the incident angle . Moreover, for small animals (lizards), subwavelength sensing employs dipolar resonances through the two internally coupled eardrums (membranes) that permit instantaneous pressure difference across the membrane . Despite their promising performance, the bioinspired directional sensors based on such an internal coupling or structurally coupled resonators pose challenges associated with dedicated sensing components and a limited sensing range (i.e., from 0° only up to 180°).…”

Section: Introductionmentioning

confidence: 99%

Fano‐Like Acoustic Resonance for Subwavelength Directional Sensing: 0–360 Degree Measurement

Lee

Nomura

et al. 2020

Advanced Science

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Directional sound sensing plays a critical role in many applications involving the localization of a sound source. However, the sensing range limit and fabrication difficulties of current acoustic sensing technologies pose challenges in realizing compact subwavelength direction sensors. Here, a subwavelength directional sensor is demonstrated, which can detect the angle of an incident wave in a full angle range (0°∼360°). The directional sensing is realized with acoustic coupling of Helmholtz resonators each supporting a monopolar resonance, which are monitored by conventional microphones. When these resonators scatter sound into free‐space acoustic modes, the scattered waves from each resonator interfere, resulting in a Fano‐like resonance where the spectral responses of the constituent resonators are drastically different from each other. This work provides a critical understanding of resonant coupling as well as a viable solution for directional sensing.

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How Internally Coupled Ears Generate Temporal and Amplitude Cues for Sound Localization

Cited by 39 publications

References 14 publications

Frequency tuning and directional sensitivity of tympanal vibrations in the field cricketGryllus bimaculatus

Frequency tuning and directional sensitivity of tympanal vibrations in the field cricketGryllus bimaculatus

Animals and ICE: meaning, origin, and diversity

Fano‐Like Acoustic Resonance for Subwavelength Directional Sensing: 0–360 Degree Measurement

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