Abstract
The basilar membrane (BM) in the greater horseshoe bat has a peculiar thickness and width profile, which suggests that BM-stiffness in the basal half turn is more than one order of magnitude greater than in the second half turn and more apically. The transition is quite abrupt.
Motivated by new data on the cochlear frequency map we analyse the possibility that the stiffer basal half turn acts as an acoustic interference filter. Its increased stiffness and impedance transitions at the stapes and at the transition mentioned, make this a feasible mechanism. We propose that 2¼ wavelengths of the reflected call frequency of the echolocating bat match the length of the interference filter. Using a scaled version of the middle ear description given by Matthews (1980) and linear, passive, long-wave, 1-dimensional cochlear mechanics we analyse the effect of the interference filter and compute the tympanic membrane input impedance. Experimental data on the latter (Wilson and Bruns, 1983a) are interpreted in terms of the proposed mechanism: fine structure in the input impedance appears to reflect the interference filter passbands.
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References
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© 1986 Springer-Verlag Berlin Heidelberg
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Duifhuis, H., Vater, M. (1986). On the Mechanics of the Horseshoe Bat Cochlea. In: Allen, J.B., Hall, J.L., Hubbard, A.E., Neely, S.T., Tubis, A. (eds) Peripheral Auditory Mechanisms. Lecture Notes in Biomathematics, vol 64. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-50038-1_12
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DOI: https://doi.org/10.1007/978-3-642-50038-1_12
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