Veselka et al. reply

• Published in: Nature (London) Vol. 466; no. 7309; p. E7
• Main Authors: Veselka, Nina, McErlain, David D, Holdsworth, David W, Eger, Judith L, Chhem, Rethy K, Mason, Matthew J, Brain, Kirsty L, Faure, Paul A, Fenton, M. Brock
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19-08-2010
• Subjects: 631/378/2619; 631/45/535; 631/601/18; brief-communications-arising; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature09157

Replying to: U. Wittrock Nature 466, 10.1038/nature09156 (2010)Wittrock suggests that a stylohyal-tympanic connection in laryngeally echolocating bats as the one described in our studycould transmit laryngeal vibrations to both ears. This could represent a 'local oscillator', forming part of a heterodyne-like detection system for precise target detection and localization. The essence of this exciting idea is that the externally transmitted echo (signal of interest) received by the ears would be mixed (multiplied) with an internally transmitted copy of the outgoing biosonar sound (reference signal) via vibrations of the stylohyal. The multiplicative mixing would generate two new signals-one at the sum and the other at the difference of the original inputs-and after low-pass filtering the remaining components would include a difference frequency signal that varied in its rate of amplitude modulation (AM).