Nanopores underlie our ability to tune in to a single voice

David L. Chandler, MIT News Office

Even in a crowded room full of background noise, the human ear is remarkably adept at tuning in to a single voice — a feat that has proved remarkably difficult for computers to match. A new analysis of the underlying mechanisms, conducted by researchers at MIT, has provided insights that could ultimately lead to better machine hearing, and perhaps to better hearing aids as well.

Our ears’ selectivity, it turns out, arises from evolution’s precise tuning of a tiny membrane, inside the inner ear, called the tectorial membrane. The viscosity of this membrane — its firmness, or lack thereof — depends on the size and distribution of tiny pores, just a few tens of nanometers wide. This, in turn, provides mechanical filtering that helps to sort out specific sounds. Read more...

This optical microscope image depicts wave motion in a cross-section of the tectorial membrane, part of the inner ear. This membrane is a microscale gel, smaller in width than a single human hair, and it plays a key role in stimulating sensory receptors of the inner ear. Waves traveling on this membrane control our ability to separate sounds of varying pitch and intensity.   



Tuesday, March 18, 2014