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BP: Fachverband Biologische Physik

BP 14: Posters: Neurobiophysics, Theoretical Neuroscience, Sensory Transduction

BP 14.2: Poster

Monday, March 14, 2011, 17:15–20:00, P3

Noise reduction in systems of coupled hair bundles — •Kai Dierkes, Benjamin Lindner, and Frank Jülicher — Max Planck Institute for the Physics of Complex Systems, Dresden

Auditory signal detection relies on amplification to boost sound-induced vibrations within the inner ear. Active motility of sensory hair-cell bundles has been suggested to constitute a decisive component of this amplifier. The responsiveness of a single hair bundle to periodic stimulation, however, is limited by intrinsic fluctuations. In vivo, hair bundles are often attached to overlying membranes. Such elastic coupling can synchronize hair-bundle motions and lead to an effective noise reduction, thus enhancing a hair bundle’s sensitivity and frequency selectivity (Dierkes et al. (PNAS, 2008), Barral et al. (PNAS, 2010)). Here, we discuss the mechanism underlying this coupling-induced noise reduction within the framework of a mean-field type argument. In particular, we show that for strong coupling, fluctuations limiting a hair bundle’s responsiveness are effectively reduced in proportion to the number of coupled hair bundles.