Cochlear Type II Neurons In Contralateral Suppression
Funder
National Health and Medical Research Council
Funding Amount
$459,434.00
Summary
Sound in one ear affects hearing in the other ear. This contralateral suppression is important for hearing attention and protection from noise damage. We will test the hypothesis that cochlear type II sensory neurons provide the sensory input for this process using models where neuronal development is altered, or the neurons are removed. The study addresses hearing disability in society, facilitating cochlear prosthesis development and the understanding of hearing loss.
Intrinsic Hearing Protection Mechanisms: A Pathway To Prevention Of Noise-induced Hearing Loss
Funder
National Health and Medical Research Council
Funding Amount
$625,900.00
Summary
Noise-induced hearing loss (NIHL) is a significant contributor to the total burden of disease. We recently determined that when the ear is exposed to sustained noise, the cochlea is protected from damage by activation of a specific (P2X2) receptor, evident as reversible hearing adaptation. This study will determine the downstream signalling from this receptor. This will support assessment of vulnerability to NIHL and contribute to development of hearing therapeutics.
Hearing Protection Conferred By P2X2 Receptor Signaling In The Cochlea
Funder
National Health and Medical Research Council
Funding Amount
$580,019.00
Summary
Hearing loss from noise damage and ageing is the principal sensory disability in our society. This project will determine the contribution of the P2X2 receptor to protection from noise-induced hearing loss. We have found that P2X2 knockout mice have minimal temporary threshold shift. We will investigate the physiological basis for this and determine why this mouse model has greater hearing loss with intense sound and faster age-related hearing loss compared with wildtype controls.
Physiological significance of transient receptor potential (TRPC3) ion channels in the cochlea. The project seeks to discover the function of transient receptor potential (TRPC3) ion channels in the cochlea. Recent studies have suggested that these proteins, which are expressed by the sensory and neural cells, are key elements regulating sound transduction and neurotransmission. The new knowledge about the physiological processes underlying hearing that this work will provide, will significantl ....Physiological significance of transient receptor potential (TRPC3) ion channels in the cochlea. The project seeks to discover the function of transient receptor potential (TRPC3) ion channels in the cochlea. Recent studies have suggested that these proteins, which are expressed by the sensory and neural cells, are key elements regulating sound transduction and neurotransmission. The new knowledge about the physiological processes underlying hearing that this work will provide, will significantly benefit national and international translational research that seeks to develop systems for controlling the sensitivity of our senses, developing biosensors, interacting with neural networks and developing neural prostheses. International collaborators in this project have enabled development of new models, technology and research training opportunities.Read moreRead less
Suction pipette measurements of mammalian rod photoreceptor recovery following intense bleaching exposures. The aim of this project is to discover the events and processes that prevent retinal photoreceptors from recovering instantaneously following the cessation of exposure to extremely bright illumination. Recordings will be made from single rod photoreceptors cells isolated from the mammalian retina. The work will uncover the relative roles of the 'photoproducts' created when rhodopsin abso ....Suction pipette measurements of mammalian rod photoreceptor recovery following intense bleaching exposures. The aim of this project is to discover the events and processes that prevent retinal photoreceptors from recovering instantaneously following the cessation of exposure to extremely bright illumination. Recordings will be made from single rod photoreceptors cells isolated from the mammalian retina. The work will uncover the relative roles of the 'photoproducts' created when rhodopsin absorbs light: e.g. intermediates such as metarhodopsin and opsin. The molecular knowledge obtained will help us to understand why it is that the visual system recovers so slowly after the eye has experienced very intense light.Read moreRead less
The first stage of vision: transduction and adaptation in retinal photoreceptors. The project aims to provide a detailed understanding of the molecular steps involved in the first stage of vision - the conversion of light into a neural signal in the rod and cone photoreceptors of the retina. The significance of this is that it will explain the initial events that enable us to see, and will help explain the deficits that occur when the process fails. The outcome will be a comprehensive understand ....The first stage of vision: transduction and adaptation in retinal photoreceptors. The project aims to provide a detailed understanding of the molecular steps involved in the first stage of vision - the conversion of light into a neural signal in the rod and cone photoreceptors of the retina. The significance of this is that it will explain the initial events that enable us to see, and will help explain the deficits that occur when the process fails. The outcome will be a comprehensive understanding of how our photoreceptors respond with extreme sensitivity, yet great rapidity, and over an enormous range of light intensities, thus endowing us with our remarkable sense of vision.Read moreRead less
A contractile cochlear frame - a possible new mechanism of sound adaptation. It is generally accepted that the rigid frame that harbours sensory structures in the hearing organs of modern higher vertebrates has only a passive supporting role. We have discovered a contractile component in the cartilaginous cochlear frame of the lizard Teratoscincus scincus and demonstrated that the tonus of the contractile tissue can be regulated. We hypothesize a new, previously unknown mechanism of slow mechani ....A contractile cochlear frame - a possible new mechanism of sound adaptation. It is generally accepted that the rigid frame that harbours sensory structures in the hearing organs of modern higher vertebrates has only a passive supporting role. We have discovered a contractile component in the cartilaginous cochlear frame of the lizard Teratoscincus scincus and demonstrated that the tonus of the contractile tissue can be regulated. We hypothesize a new, previously unknown mechanism of slow mechanical adaptation in the vertebrate hearing organ. The aim of the proposed project is to examine this hypothesis in more detail.
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Evolution of sound localisation in vertebrates: head size, sound frequency and neural phase-locking. Hearing is our most important sense for interpersonal communication, yet we have a fragmentary understanding of the basic mechanisms involved in normal hearing. This project addresses the question of how sound location is represented in the brain through the processing of minute time difference with which sounds reach the two ears. The outcome will ultimately enable us to infer how the human brai ....Evolution of sound localisation in vertebrates: head size, sound frequency and neural phase-locking. Hearing is our most important sense for interpersonal communication, yet we have a fragmentary understanding of the basic mechanisms involved in normal hearing. This project addresses the question of how sound location is represented in the brain through the processing of minute time difference with which sounds reach the two ears. The outcome will ultimately enable us to infer how the human brain localises sound, with practical applications for improved virtual auditory realities and hearing aids.Read moreRead less
Central Representation of Electroacoustic Stimuli. Cochlear implantation, initially only provided to profoundly deaf individuals, is now routine in people with substantial residual hearing. Although stimulation via a cochlear implant and hearing aid in the same ear has been shown to improve speech understanding, particularly in noise, and to increase the aesthetic quality of sound, almost nothing is known about the physiological mechanisms underlying these benefits. The broad aim of our project ....Central Representation of Electroacoustic Stimuli. Cochlear implantation, initially only provided to profoundly deaf individuals, is now routine in people with substantial residual hearing. Although stimulation via a cochlear implant and hearing aid in the same ear has been shown to improve speech understanding, particularly in noise, and to increase the aesthetic quality of sound, almost nothing is known about the physiological mechanisms underlying these benefits. The broad aim of our project is to address this deficiency by measuring the patterns of neural activity evoked by speech sounds across the tonotopic axis in the inferior colliculus and auditory cortex and assess the extent to which the pattern of neural activity allows discrimination between the different speech sounds.Read moreRead less
The research will investigate the mechanisms by which our brains are able to listen selectively to sounds of interest in competing background noise. This will be investigated in normal hearing subjects, those with partial deafness and in profoundly deaf patients who use a cochlear implant. If deaf patients can learn to use cues to enhance detection of sounds of interest this could have an impact on the effectiveness of hearing aids and cochlear implants in noisy listening situations