A new study into hearing has uncovered the secret of our extraordinary ability to perceive a range of sounds, and could lead to a better understanding of deafness and hearing loss, says a statement from Deafness Research UK, London.
The researchers say they hope that further research could lead to understanding mechanisms behind deafness, enabling improved methods aimed at repairing hearing loss due to damage or genetic defects.
Funded by the Wellcome Trust, Deafness Research UK and the Royal Society, Walter Marcotti, PhD, of the Sheffield University’s Department of Biomedical Science, UK, has discovered how a particular calcium sensor present in highly specialized sensory cells allows us to hear with such remarkable sensitivity across a wide range of sound intensities, says the statement.
Working collaboratively with researchers in four other institutions, Marcotti and his research assistant Dr Stuart Johnson have found that a calcium sensor present in auditory sensory cell synapses allows them to encode graded sound stimuli. Their findings have been published in the journal Nature Neuroscience.
The human ear can process an impressive range of sounds, from a pin dropping to a jet engine on takeoff. This remarkable achievement depends upon the ability of these sensory receptors to respond to graded signals across a wide range of sound intensity. A similar phenomenon exists in other sensory systems, including the eye. The system depends on the properties of specialised ribbon synapses that convey sensory information from the receptors to the brain.
"The function of this specific calcium sensor is to extend the dynamic range of sensory synapses in order to increase hearing sensitivity across such a wide spectrum of sound intensities," said Marcotti and Johnson in the statement. "We are now studying how the calcium sensors, or synaptotagmins, interact to produce our remarkably sensitive auditory, visual and olfactory systems." By revealing the main determinants of normal cochlear synaptic development, they say they hope the information gathered could bring us closer to an understanding of mechanisms behind deafness, and improve methods aimed at repairing hearing loss due to damage or genetic defects.
Deafness Research UK aims to find cures, treatments, and technologies for deaf, hard-of-hearing, and other hearing-impaired individuals.
[Source: Deafness Research UK]