Contrôle de la taille de la touffe ciliaire des cellules mécanosensorielles ciliées pour une détection auditive sélective en fréquence

par Atitheb Chaiyasitdhi

Projet de thèse en Frontières du vivant

Sous la direction de Pascal Martin et de Christine Petit.

Thèses en préparation à Paris Sciences et Lettres , dans le cadre de Frontières du vivant , en partenariat avec PhysicoChimie (laboratoire) et de Institut Curie (Paris) (établissement de préparation de la thèse) depuis le 02-10-2017 .


  • Résumé

    Auditory processing of complex sounds like speech or music relies on acute frequency discrimination over a broad range of sound frequencies. To cope with this requirement, the cochlea of the inner ear is endowed with specialized mechanosensory “hair cells” that are each tuned to detect a particular frequency of sound-evoked vibration. Tuning results in part from the mechanical properties of the hair bundle, the mechanosensory antenna of the hair cell. Morphological gradients within the cochlea suggest that the hair bundle operates as a (living) tuning fork for which size helps select the preferred frequency of vibration. Despite its critical importance for hearing, the mechanism that specifies the morphology of the hair bundle in relation to the characteristic frequency of the corresponding hair cell is largely unknown. To clarify this major question of auditory physiology, the PhD candidate will study the role played by mechanical tension in proteinaceous links that interconnect the “hairs” (stereocilia) of the hair bundle. The work will benefit from an ongoing collaboration between our group at the Curie Institute, which brings the biophysical tools to experimentally probe and theoretically describe the effect of mechanical force on the hair bundle, and the group led by Prof Christine Petit (Institut Pasteur), which brings genetically modified mice that present defects in the morphology of the hair bundle as well as a biochemical know-how to identify, visualize and interfere with molecular constituents of this organelle. Defects in the morphology of the hair-cell bundle result in severe hearing deficits. By better understanding how this morphology is tuned according to the bundle's function as a frequencyselective mechanosensor, as well as by finding the physical origin of its deterioration in deaf animals, we hope to lay the groundwork for some future therapeutic approaches of deafness of genetic or environmental origin.

  • Titre traduit

    Size control of the hair-cell bundle for frequency-selective auditory detection


  • Résumé

    Auditory processing of complex sounds like speech or music relies on acute frequency discrimination over a broad range of sound frequencies. To cope with this requirement, the cochlea of the inner ear is endowed with specialized mechanosensory “hair cells” that are each tuned to detect a particular frequency of sound-evoked vibration. Tuning results in part from the mechanical properties of the hair bundle, the mechanosensory antenna of the hair cell. Morphological gradients within the cochlea suggest that the hair bundle operates as a (living) tuning fork for which size helps select the preferred frequency of vibration. Despite its critical importance for hearing, the mechanism that specifies the morphology of the hair bundle in relation to the characteristic frequency of the corresponding hair cell is largely unknown. To clarify this major question of auditory physiology, the PhD candidate will study the role played by mechanical tension in proteinaceous links that interconnect the “hairs” (stereocilia) of the hair bundle. The work will benefit from an ongoing collaboration between our group at the Curie Institute, which brings the biophysical tools to experimentally probe and theoretically describe the effect of mechanical force on the hair bundle, and the group led by Prof Christine Petit (Institut Pasteur), which brings genetically modified mice that present defects in the morphology of the hair bundle as well as a biochemical know-how to identify, visualize and interfere with molecular constituents of this organelle. Defects in the morphology of the hair-cell bundle result in severe hearing deficits. By better understanding how this morphology is tuned according to the bundle's function as a frequencyselective mechanosensor, as well as by finding the physical origin of its deterioration in deaf animals, we hope to lay the groundwork for some future therapeutic approaches of deafness of genetic or environmental origin.