How Nanopores Help Us Filter Sound

One of the great mysteries of auditory research is being cracked by a team of researchers from the Massachusetts Institute of Technology. It has long been known that the human ear is unmatched in its ability to focus on a single voice, even in a roomful of competing sounds. However, the precise mechanism working to allow such filtering of sounds has been not well understood. New research provides insight into the structure of the human ear and, ultimately, will lead to better machine hearing and even more powerful hearing aids.

The research, published in Biophysics Journal, determined that a tiny membrane in the inner ear provides an actual filter for sound. This membrane, called the tectorial membrane, is critical. The membrane's structure determines how well it filters sound. The tectorial membrane is sponge-like, filled with microscopic pores (also called nanopores). Researchers studied two genetic variants that cause the pores within the tectorial membrane to be smaller or larger than normal. The pore size affects the viscosity of the membrane and its sensitivity to different frequencies. There is an optimum size of these tiny pores that allows for the best hearing.

One MIT researcher, Roozbeh Ghaffari, sums up this new understanding, stating, “It really changes the way we think about this structure."

While the research is still evolving, the new findings do point to a relationship among fluid viscosity and pores critical to hearing. Researchers speculate that future advances in changing the sizes of tectorial membrane nanopores, via biochemical manipulation or other means, may provide new ways to improve damaged hearing. While we may never fully decipher how humans can filter sound, the research into the mystery may uncover new understandings that can translate into therapies for the hearing-impaired.

Source: Science Daily

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