Mathematicians at Vanderbilt University have created a mathematical model of the cochlea and use the model to show that the spiral shape acts to enhance the low frequency sounds. The researchers led by Daphne Manoussaki and her colleagues, Richard Chadwick and Emilios Dimitriadis of the National Institutes of Health, published their findings in the journal Physical Review Letters.
See the full journal article
D. Manoussaki, E. Dimitriadis and R.S. Chadwick. The cochlea’s graded curvature effect on low frequency waves, Physical Review Letters 96, 088701 (issue of March 3, 2006).
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Abstract:
In the ear, sound waves are processed by a membrane of graded mechanical properties that resides in the fluid-filled spiral cochlea. The role of stiffness grading as a Fourier analyzer is well known, but the role of the curvature has remained elusive. Here, we report that increasing curvature redistributes wave energy density towards the cochlea’s outer wall, affecting the shape of waves propagating on the membrane, particularly in the region where low frequency sounds are processed.