Winter 2015

The Energetic Ear

Albert James Hudspeth

As the gateway to human communication, the sense of hearing is of enormous importance in our lives. Research on hearing has recently been revolutionized by the demonstration that the ear is not simply a passive receiver for sound, but also an amplifier that augments, filters, and compresses its inputs. Hair cells, the ear's sensory receptors, use two distinct methods to implement an active process that endows our hearing with these remarkable properties. First, the vibration-sensitive structures of the ear, called hair bundles, display a mechanical instability that allows them to oscillate in response to stimulation. And second, the membranes of hair cells are replete with proteins that contract in response to electrical stimuli, thus enabling the cells to act like tiny muscles. The activity of these two motile processes can be so exuberant as to cause normal ears to emit sounds.

A. J. HUDSPETH, a Fellow of the American Academy since 2002, is the F. M. Kirby Professor and Head of the Laboratory of Sensory Neuroscience at the Rockefeller University. He is also an Investigator at the Howard Hughes Medical Institute and a member of the National Academy of Sciences. His research has been published in journals such as The Journal of Neuroscience, Nature Reviews Neuroscience, Nature, and Neuron; he recently coedited the fifth edition of the textbook Principles of Neural Science (2013).

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