Acoustic Control in the Flight of Bats

Hartridge, H.

doi:10.1038/156490a0

Cited by 49 publications

(22 citation statements)

References 6 publications

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“…Echolocating bats use the time delay between sonar emission and returning echo to determine the distance to a target (Hartridge 1945). This was first demonstrated experimentally by Simmons (1973), who trained bats in a 2-AFC procedure to discriminate the distance between two targets positioned at different ranges.…”

Section: Range Difference Discriminationmentioning

confidence: 99%

Behavioral Studies of Auditory Information Processing

Moss¹,

Schnitzler²

1995

Springer Handbook of Auditory Research

118

100

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Section: Range Difference Discriminationmentioning

confidence: 99%

Behavioral Studies of Auditory Information Processing

Moss¹,

Schnitzler²

1995

Springer Handbook of Auditory Research

118

100

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“…Binaural differences in arrival time, intensity, and spectrum of echoes encode the location of an object in azimuth and elevation (Lawrence and Simmons, 1982;Simmons et al, 1983;Pollak, 1988). The third dimension, the distance between the bat and a target, is determined from the time delay between the outgoing sound and the returning echo (Hartridge, 1945;Simmons, 1973). Together, these cues provide the bat with information to form an estimate of a target's position in three-dimensional space.…”

mentioning

confidence: 99%

Spatially Selective Auditory Responses in the Superior Colliculus of the Echolocating Bat

Valentine

Moss

1997

J. Neurosci.

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When a bat approaches a target, it continuously modifies its echolocation sounds and relies on incoming echo information to shape the characteristics of its subsequent sonar cries. In addition, acoustic information about the azimuth and elevation of a sonar target elicits orienting movements of the head and pinnae toward the sound source. This requires a common sensorimotor interface, where echo information is used to guide motor behaviors.Using single-unit neurophysiological methods and free-field auditory stimulation, we present data on biologically relevant specializations in the superior colliculus (SC) of the bat for orientation by sonar. In the bat's SC, two classes of spatially tuned neurons are distinguished by their sensitivity to echoes. One population shows facilitated, delay-tuned responses to pairs of sounds, simulating sonar emissions and echoes. Delay tuning, related to encoding target range, may play a role in guiding motor responses in echolocation, because the bat adjusts its emissions with changes in target distance. The delay-facilitated response depends on the direction of stimulation and on the temporal relationship between the simulated emission and echo in the sound pair, suggesting that this class of neurons represents the location of a target in three dimensions. A second population encodes the target in two dimensions, azimuth and elevation, and does not show a facilitated response to echoes delivered from any locus. Encoding of azimuth and elevation may be important for directing head aim, and this class may function in transforming auditory spatial information into signals used to guide acoustic orientation. Key words: superior colliculus; echolocation; bats; acoustic orientation; spatial perception; sensorimotor integrationThe midbrain superior colliculus (SC; optic tectum) of vertebrates is thought to play a role in spatial perception and in the translation of multisensory signals into commands for the control of quick (saccadic) orienting responses. In individual species, the organization of the SC reflects the importance of a particular sensory modality to an animal's goal-directed behavioral responses. By analogy with the role of the SC in the saccadic eye-movement system of primates (Sparks, 1986), in gaze-control orientation behavior in cat and barn owl (Knudsen, 1982;Middlebrooks and Knudsen, 1984;Du Lac and Knudsen, 1990;Munoz et al., 1991), and in prey-catching behavior in pit viper and frog (Hartline et al., 1978;Grobstein, 1988), the SC of the echolocating bat may play a role in integrating sensory and motor signals that drive this animal's acoustic orientation by sonar.The bat guides its flight and forages in darkness by emitting ultrasonic vocal signals and listening to the echoes returning to its ears from objects in space (Griffin, 1958;Moss and Schnitzler, 1995). Binaural differences in arrival time, intensity, and spectrum of echoes encode the location of an object in azimuth and elevation (Lawrence and Simmons, 1982;Simmons et al., 1983;Pollak, 1988). The third dim...

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“…[13][14][15] Au and Simmons, 15 somewhat controversially, concluded that bats using pulses with a center frequency of about 80 kHz ͑40 kHz bandwidth͒ can achieve a distance resolution in air approaching 20 m. At this frequency, and using / 2 as the guide for resolution, we see that the resolution reported by Au and Simmons is about 200 times better than that predicted conventionally. We sought to develop a methodology which would allow us to approach a resolution comparable to that achieved by such creatures which is still better than any man-made system.…”

Section: A Conceptmentioning

confidence: 65%

Short pulse multi-frequency phase-based time delay estimation

Assous

Hopper

Lovell

et al. 2010

The Journal of the Acoustical Society of America

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An approach for time delay estimation, based on phase difference detection, is presented. A multiple-frequency short continuous wave pulse is used to solve the well-known phase ambiguity problem when the maximum distance exceeds a full wavelength. Within an unambiguous range defined with the lowest frequency difference between components, the corresponding phase difference is unique and any distance within this range can be determined. Phase differences between higher frequency components are used to achieve a finer resolution. The concept will be presented and the effectiveness of the approach will be investigated through theoretical and practical examples. The method will be validated using underwater acoustic measurements, simulating noisy environments, demonstrating resolutions better than a 50th of a wavelength, even in the presence of high levels ͑−5 dB͒ of additive Gaussian noise. Furthermore, the algorithm is simple to use and can be easily implemented, being based on phase detection using the discrete Fourier transform.

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Acoustic Control in the Flight of Bats

Cited by 49 publications

References 6 publications

Behavioral Studies of Auditory Information Processing

Behavioral Studies of Auditory Information Processing

Spatially Selective Auditory Responses in the Superior Colliculus of the Echolocating Bat

Short pulse multi-frequency phase-based time delay estimation

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