The tectorial membrane: one slice of a complex cochlear sandwich.

The review is both timely and relevant, as recent findings have shown the tectorial membrane plays a more dynamic role in hearing than hitherto suspected, and that many forms of deafness can result from mutations in tectorial membrane proteins. Main themes covered are the molecular composition, the structural organization and properties of the tectorial membrane, the role of the tectorial membrane as a second resonator and a structure within which there is significant longitudinal coupling, and how mutations in tectorial membrane proteins cause deafness in mice and men. Findings from experimental models imply that the tectorial membrane plays multiple, critical roles in hearing. These include coupling elements along the length of the cochlea, supporting a travelling wave and ensuring the gain and timing of cochlear feedback are optimal. The clinical findings suggest stable, moderate-to-severe forms of hereditary hearing loss may be diagnostic of a mutation in TECTA, a gene encoding one of the major, noncollagenous proteins of the tectorial membrane.