The mammalian auditory sensory epithelium, the organ of Corti, comprises the hair cells and supporting cells that are pivotal for hearing function. The origin and development of their precursors are poorly understood. Here we show that loss-of-function mutations in mouse fibroblast growth factor receptor 1 (Fgfr1) cause a dose-dependent disruption of the organ of Corti. Full inactivation of Fgf...

Auditory models reverse processing techniques would have very useful applications in speech perception and auditory models evaluation. This paper examines how we can be benefit an Inner Hair Cell (IHC) model as a compression and envelope detection section, in the cochlear model inverse processing. Our proposed inversion method, combines the reverse of the Meddis’s auditory neural transduction m...

Auditory perception in vertebrates depends on transduction of sound into neural signals in the inner ear hair cells (HCs) and on transmission of these signals to the brain through auditory (VIIIth) nerve afferents. To investigate the developmental acquisition of auditory inputs by the CNS, we have electrophysiologically and morphologically examined the process of acquisition of auditory respons...

The effects of inner ear abnormality on audibility have been explored since the early 20th century when sound detection measures were first used to define and quantify 'hearing loss'. The development in the 1970s of objective measures of cochlear hair cell function (cochlear microphonics, otoacoustic emissions, summating potentials) and auditory nerve/brainstem activity (auditory brainstem resp...

Many animals use sound to communicate with each other, and hearing is particularly important for survival and reproduction. In species that use sound as a primary means of communication, their hearing is typically most acute for the range of pitches produced in calls and speech. Human is one such species and Fig. 1 shows a human ear consisting of the outer, middle and inner ear. The eardrum of ...

In vertebrates, auditory and vestibular transduction occurs on apical projections (stereocilia) of specialized cells (hair cells). Mutations in myosin VIIA (myoVIIA), an unconventional myosin, lead to deafness and balance anomalies in humans, mice, and zebrafish; individuals are deaf, and stereocilia are disorganized. The exact mechanism through which myoVIIA mutations result in these inner-ear...

The fluorescent honeycomb above is the sensory epithelium of the mouse auditory organ, viewed in cross-section to show the cell bodies of the sensory hair cells. The bright green sensory hair cells have been infected with a viral vector that carries the gene for the green fluorescent protein (GFP). The tissue is counterstained for actin (red), which is abundant in the hair bundles and the peric...

Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two...

The mammalian inner ear subserves the special senses of hearing and balance. The auditory and vestibular sensory epithelia consist of mechanically sensitive hair cells and associated supporting cells. Hearing loss and balance dysfunction are most frequently caused by compromise of hair cells and/or their innervating neurons. The development of gene- and cell-based therapeutics will benefit from...