Mar. 10, 2004 Bar Harbor, Maine -- Ears do more than hear; they
also control balance and our perception of gravity and motion.
An international team of scientists including David E. Bergstrom
and John C. Schimenti, at The Jackson Laboratory in Bar Harbor;
and Rainer Paffenholz and Gabriele Stumm at Ingenium
Pharmaceuticals AG in Martinsried, Germany, identified for the
first time a protein whose enzymatic function is indispensable
for development of this balance system. The scientists had known
that mice with the head tilt mutation known as het hear
perfectly well, but carry their head at an angle and lack
coordination. Mice and humans sense motion in the same way. When
our heads move, a cluster of crystalline structures known as
otoconia in the inner ear moves somewhat independently. This
shearing motion stimulates underlying nerve endings to create
the sensation of motion. The scientists found the head-tilt mice
have no otoconia, but otherwise exhibit perfect inner ear
formation. "Because animals use otocon