New Study Casts Doubt on Old Ideas of How Hearing Works

The research study shows that numerous cells in the inner ear respond at the same time to low-frequency noise. The method human beings experience music and speech varies from what was formerly believed. This is the finding of a research study performed by scientists from Linköping University in Sweden and Oregon Health and Science University in the United States. The findings, which have actually just recently been released in the journal Science Advances might enhance cochlear implant style. We are friendly beings. We value hearing other individuals’s voices, and we utilize our hearing to acknowledge and experience human speech and voices. Noise that goes into the external ear is sent by the eardrum to the spiral-shaped inner ear, likewise called the cochlea. The cochlea is house to the external and inner hair cells, which are the sensory cells of hearing. The inner hair cells’ “hairs” flex as an outcome of the acoustic waves, providing a signal through the nerves to the brain, which translates the noise we hear. Anders Fridberger and Pierre Hakizimana determine vibrations in the hearing organ. Credit: Emma Busk Winquist/Link öping University We have actually thought for the last 100 years that each sensory cell has its own “optimum frequency” (a procedure of the variety of acoustic waves per second). This frequency generates the greatest reaction from the hair cell. This indicates that a sensory cell with a maximum frequency of 1000 Hz will react substantially less highly to noises with somewhat lower or greater frequencies. It has actually likewise been believed that all parts of the cochlea function. A research study group has actually exposed that this is not the case for sensory cells that process low-frequency noise with frequencies less than 1000 Hz. Vowel sounds in human speech fall under this classification. “Our research study reveals that numerous cells in the inner ear respond all at once to low-frequency noise. Our company believe that this makes it much easier to experience low-frequency noises than would otherwise hold true considering that the brain gets details from numerous sensory cells at the exact same time,” states Anders Fridberger, teacher in the Department of Biomedical and Clinical Sciences at Linköping University. Anders Fridberger carrying out research study. Credit: Emma Busk Winquist/Link öping University The researchers think that this building of our hearing system makes it more robust. If some sensory cells are harmed, numerous others stay that can send out nerve impulses to the brain. Anders Fridberger, teacher at Linköping University. Credit: Emma Busk Winquist/Link öping University It is not just the vowel sounds of human speech that depend on the low-frequency area: much of the noises that go to comprise music likewise lie here. Middle C on a piano, for instance, has a frequency of 262 Hz. These outcomes might become considerable for individuals with extreme hearing problems. The most effective treatment presently offered in such cases is a cochlear implant, in which electrodes are positioned into the cochlea. “The style of existing cochlear implants is based upon the presumption that each electrode ought to just offer nerve stimulation at particular frequencies, in such a way that attempts to copy what was thought about the function of our hearing system. We recommend that altering the stimulation technique at radio frequencies will be more comparable to the natural stimulation, and the hearing experience of the user ought to in this method be enhanced,” states Anders Fridberger. The scientists now prepare to take a look at how their brand-new understanding can be used in practice. Among the jobs they are examining issues brand-new approaches to promote the low-frequency parts of the cochlea. These outcomes originate from experiments on the cochlea of guinea pigs, whose hearing in the low-frequency area resembles that of people. Recommendation: “Best frequencies and temporal hold-ups are comparable throughout the low-frequency areas of the guinea pig cochlea” by George Burwood, Pierre Hakizimana, Alfred L Nuttall and Anders Fridberger, 23 September 2022, Science Advances.
DOI: 10.1126/ sciadv.abq2773 The research study was moneyed by the U.S. National Institutes of Health and the Swedish Research Council.
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