Modeling the role of nonhuman vocal membranes in phonation

Herzel, Hanspeter; Mergell, Patrick; Fitch, W. Tecumseh

doi:10.1121/1.426735

Cited by 81 publications

(66 citation statements)

References 30 publications

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“…Microchiropteran bats and other mammals that produce ultrasonic fundamental frequencies in air have thin membranes on their vocal folds (Suthers and Fattu, 1973;Mergell et al, 1999). In the big brown bat, Eptesicus fuscus, this membrane is approximately 6-8·m thick, 500·m wide and 2·mm long (Suthers and Fattu, 1973).…”

Section: Source Of Ultrasoundmentioning

confidence: 99%

Voices of the dead: complex nonlinear vocal signals from the larynx of an ultrasonic frog

Suthers

Narins

Lin

et al. 2006

Journal of Experimental Biology

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Most vertebrate species use sound to communicate intra-and inter-specifically. The vocal repertoires of vertebrate groups range widely, with mammals and especially primates having greater repertoires and call complexity than amphibians. It is often assumed that an increase in vocal complexity requires a corresponding increase in the neuromuscular machinery involved in phonation (e.g. Gaunt, 1983;Simpson and Vicario, 1990). According to this view, animals that lack sophisticated mechanisms for motor control of the vocal system are limited to producing relatively simple vocal signals. An alternative means for increasing vocal complexity involves the intrinsic nonlinear dynamics of the oscillators in the larynx or syrinx (Fee et al., 1998). The nonlinear properties of the vocal source enable very small, gradual changes in a control parameter (such as the driving respiratory pressure or rate of airflow across the oscillator) to produce abrupt changes in the vibratory mode, resulting in such nonlinear phenomena as period doubling, biphonation, abrupt frequency jumps and deterministic chaos. The relatively recent application of nonlinear dynamics theory to animal communication has fostered a growing interest in the possible importance of nonlinear phenomena in acoustic communication (Fee et al., 1998;Wilden et al., 1998; BantaLavenex, 1999;Fee, 2002;Fitch et al., 2002).We investigated the inherent nonlinear properties of the larynx of a remarkable frog, Amolops tormotus (Ranidae). Whereas most frogs produce relatively simple calls, the vocalizations of A. tormotus are unusual in several respects. First, males of this small species produce a seemingly endless variety of warbling calls that typically contain both upward and downward frequency modulations (Feng et al., 2002). Second, this frog is unique among those studied in using ultrasound for communication. Many A. tormotus calls extend well into the ultrasonic frequency range (Narins et al., 2004). It has been shown that these frogs can detect and respond to ultrasound (Feng et al., 2006). By extending its vocal communication to Most anurans are highly vocal but their vocalizations are stereotyped and simple with limited repertoire sizes compared with other vocal vertebrates, presumably because of the limited mechanisms for fine vocal motor control. We recently reported that the call of the concaveeared torrent frog (Amolops tormotus Fei) is an exception in its seemingly endless variety, musical warbling quality, extension of call frequency into the ultrasonic range and the prominence of subharmonics, chaos and other nonlinear features. We now show that the major spectral features of its calls, responsible for this frog's vocal diversity, can be generated by forcing pressurized air through the larynx of euthanized males. Laryngeal specializations for ultrasound appear to include very thin portions of the medial vocal ligaments and reverse sexual size dimorphism of the larynx -being smaller in males than in females. The intricate morphology of the vocal cords, which ...

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Section: Source Of Ultrasoundmentioning

confidence: 99%

Voices of the dead: complex nonlinear vocal signals from the larynx of an ultrasonic frog

Suthers

Narins

Lin

et al. 2006

Journal of Experimental Biology

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“…Nonlinear phenomena were virtually absent in male Diana monkey vocalizationa and pulses were not interrupted by any other vibration modes of the vocal folds, except for the short harmonic intercall elements. Specialized system adjustments and the low fundamental frequency could account for the remarkable stability of the oscillating system ͑but see Mergell et al, 1999͒.…”

Section: A Source Acousticsmentioning

confidence: 99%

The relationship between acoustic structure and semantic information in Diana monkey alarm vocalization

Riede

Zuberbühler

2003

The Journal of the Acoustical Society of America

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Mammalian vocal production mechanisms are still poorly understood despite their significance for theories of human speech evolution. Particularly, it is still unclear to what degree mammals are capable of actively controlling vocal-tract filtering, a defining feature of human speech production. To address this issue, a detailed acoustic analysis on the alarm vocalization of free-ranging Diana monkeys was conducted. These vocalizations are especially interesting because they convey semantic information about two of the monkeys' natural predators, the leopard and the crowned eagle. Here, vocal tract and sound source parameter in Diana monkey alarm vocalizations are described. It is found that a vocalization-initial formant downward transition distinguishes most reliably between eagle and leopard alarm vocalization. This finding is discussed as an indication of articulation and alternatively as the result of a strong nasalization effect. It is suggested that the formant modulation is the result of active vocal filtering used by the monkeys to encode semantic information, an ability previously thought to be restricted to human speech.

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“…Nonlinear phenomena are relevant in this context because they can be directly related to events at the laryngeal source. Several lines of research suggest that nonlinear phenomena are common and ubiquitous in mammalian vocalization behavior ͑Wilden et Mergell et al, 1999;Riede et al, 1997Riede et al, , 2000Fischer et al, 2000͒. Phenomena such as frequency jumps, subharmonics, biphonation, and deterministic chaos are commonly observed, usually the result of deviations from the regular harmonic vibration pattern of the vocal folds, such as nonsynchronously oscillating left and right vocal folds or simultaneously oscillating horizontal and vertical components of the vocal folds ͑e.g., Herzel et al, 1994;Berry, 2001;Berry et al, 1994;Steinecke and Herzel, 1995;Tigges et al, 1997;Neubauer et al, 2001͒. The two combined approaches are likely to yield important insights into the sound production mechanism underlying male Diana monkey alarm calls.…”

Section: Introductionmentioning

confidence: 99%

Pulse register phonation in Diana monkey alarm calls

Riede

Zuberbühler

2003

The Journal of the Acoustical Society of America

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The adult male Diana monkeys ͑Cercopithecus diana͒ produce predator-specific alarm calls in response to two of their predators, the crowned eagles and the leopards. The acoustic structure of these alarm calls is remarkable for a number of theoretical and empirical reasons. First, although pulsed phonation has been described in a variety of mammalian vocalizations, very little is known about the underlying production mechanism. Second, Diana monkey alarm calls are based almost exclusively on this vocal production mechanism to an extent that has never been documented in mammalian vocal behavior. Finally, the Diana monkeys' pulsed phonation strongly resembles the pulse register in human speech, where fundamental frequency is mainly controlled by subglottal pressure. Here, we report the results of a detailed acoustic analysis to investigate the production mechanism of Diana monkey alarm calls. Within calls, we found a positive correlation between the fundamental frequency and the pulse amplitude, suggesting that both humans and monkeys control fundamental frequency by subglottal pressure. While in humans pulsed phonation is usually considered pathological or artificial, male Diana monkeys rely exclusively on pulsed phonation, suggesting a functional adaptation. Moreover, we were unable to document any nonlinear phenomena, despite the fact that they occur frequently in the vocal repertoire of humans and nonhumans, further suggesting that the very robust Diana monkey pulse production mechanism has evolved for a particular functional purpose. We discuss the implications of these findings for the structural evolution of Diana monkey alarm calls and suggest that the restricted variability in fundamental frequency and robustness of the source signal gave rise to the formant patterns observed in Diana monkey alarm calls, used to convey predator information.

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Modeling the role of nonhuman vocal membranes in phonation

Cited by 81 publications

References 30 publications

Voices of the dead: complex nonlinear vocal signals from the larynx of an ultrasonic frog

Voices of the dead: complex nonlinear vocal signals from the larynx of an ultrasonic frog

The relationship between acoustic structure and semantic information in Diana monkey alarm vocalization

Pulse register phonation in Diana monkey alarm calls

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