Berlin 2008 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 3: Neuronal Systems

BP 3.11: Vortrag

Montag, 25. Februar 2008, 17:00–17:15, C 243

Mechanical properties of coupled hair bundles — •Kai Dierkes, Frank Jülicher, and Benjamin Lindner — Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany

In all vertebrates the hair bundle is the mechano-electrical transducer in both the auditory and the vestibular system. In contrast to being purely passive resonators hair bundles from the sacculus of the bullfrog have been shown to possess the ability to amplify weak periodic stimuli by means of an active process. Spontaneous and evoked oscillations of single hair bundles in lower vertebrates have been studied in order to probe the underlying mechanism. Recently Nadrowski at al. (PNAS 2004) have proposed a model for active hair bundle motility that very well captures the experimental findings. In vivo hair bundles in the sacculus of the bullfrog are attached to an overlying structure that effectively mediates a coupling between them: the otolithic membrane. The same holds true for the hair bundles of outer hair cells in the mammalian cochlea whose tips are connected to the overlying tectorial membrane. We report on results that suggest that collective effects in arrays of coupled hair bundles could indeed play a significant role for signal detection in inner ear organs.