Hyperacute directional hearing in a microscale auditory system

The physics of sound propagation imposes fundamental constraints on sound localization: for a given frequency, the smaller the receiver, the smaller the available cues. Thus, the creation of nanoscale acoustic microphones with directional sensitivity is very difficult. The fly Ormia ochracea possess...

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Bibliographic Details
Published in:Nature (London) 2001-04, Vol.410 (6829), p.686-690
Main Authors: Mason, Andrew C, Oshinsky, Michael L, Hoy, Ron R
Format: Article
Language:English
Subjects:
Acoustics
Animal Communication
Animals
Biochemistry. Physiology. Immunology
Biological and medical sciences
Body Constitution
Diptera - anatomy & histology
Diptera - physiology
Ears & hearing
Equipment Design
Female
Fundamental and applied biological sciences. Psychology
Gryllidae
Hearing Aids
Humanities and Social Sciences
Humans
Insecta
Insects
Invertebrates
letter
Mechanoreceptors - physiology
Microphones
multidisciplinary
Ormia ochracea
Physics
Physiology. Development
Science
Science (multidisciplinary)
Sound Localization - physiology
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Summary:The physics of sound propagation imposes fundamental constraints on sound localization: for a given frequency, the smaller the receiver, the smaller the available cues. Thus, the creation of nanoscale acoustic microphones with directional sensitivity is very difficult. The fly Ormia ochracea possesses an unusual 'ear' that largely overcomes these physical constraints; attempts to exploit principles derived from O. ochracea for improved hearing aids are now in progress. Here we report that O. ochracea can behaviourally localize a salient sound source with a precision equal to that of humans. Despite its small size and minuscule interaural cues, the fly localizes sound sources to within 2° azimuth. As the fly's eardrums are less than 0.5 mm apart, localization cues are around 50 ns. Directional information is represented in the auditory system by the relative timing of receptor responses in the two ears. Low-jitter, phasic receptor responses are pooled to achieve hyperacute timecoding. These results demonstrate that nanoscale/microscale directional microphones patterned after O. ochracea have the potential for highly accurate directional sensitivity, independent of their size. Notably, in the fly itself this performance is dependent on a newly discovered set of specific coding strategies employed by the nervous system.
ISSN:0028-0836
1476-4687
DOI:10.1038/35070564