The research study shows that many cells in the inner ear respond concurrently to low-frequency sound.
The method humans experience music and speech differs from what was previously thought. This is the finding of a research study conducted by researchers from Linköping University in Sweden and Oregon Health and Science University in the United States. The findings, which have actually just recently been published in the journal Science Advances might improve cochlear implant style.
We are sociable beings. We value hearing other individualss voices, and we use our hearing to acknowledge and experience human speech and voices. Noise that enters the outer ear is transferred by the eardrum to the spiral-shaped inner ear, likewise known as the cochlea. The cochlea is home to the outer and inner hair cells, which are the sensory cells of hearing. The inner hair cells “hairs” bend as an outcome of the acoustic waves, delivering 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 believed for the last 100 years that each sensory cell has its own “optimal frequency” (a step of the number of sound waves per second). This suggests that a sensory cell with an optimum frequency of 1000 Hz will react significantly less strongly to noises with somewhat lower or greater frequencies. A research group has actually exposed that this is not the case for sensory cells that process low-frequency sound with frequencies less than 1000 Hz.
” Our study reveals that lots of cells in the inner ear respond at the same time to low-frequency sound. Our company believe that this makes it much easier to experience low-frequency sounds than would otherwise be the case since the brain receives info from many sensory cells at the very same time,” says 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 believe that this building and construction of our hearing system makes it more robust. If some sensory cells are harmed, many others remain that can send out nerve impulses to the brain.
Anders Fridberger, professor at Linköping University. Credit: Emma Busk Winquist/Link öping University.
It is not only the vowel sounds of human speech that depend on the low-frequency area: a number of the noises that go to make up music also lie here. Middle C on a piano, for instance, has a frequency of 262 Hz.
These results may ultimately be substantial for people with serious hearing problems. The most successful treatment presently offered in such cases is a cochlear implant, in which electrodes are positioned into the cochlea.
” The style of current cochlear implants is based upon the presumption that each electrode should just offer nerve stimulation at certain frequencies, in a manner that tries to copy what was believed about the function of our hearing system. We recommend that changing the stimulation method at low frequencies will be more comparable to the natural stimulation, and the hearing experience of the user need to in this method be improved,” states Anders Fridberger.
The researchers now plan to examine how their new knowledge can be applied in practice. Among the projects they are investigating concerns new techniques to stimulate the low-frequency parts of the cochlea.
These results come from experiments on the cochlea of guinea pigs, whose hearing in the low-frequency area resembles that of people.
Reference: “Best frequencies and temporal hold-ups are similar throughout the low-frequency regions 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.
Sound that enters the outer ear is transferred by the eardrum to the spiral-shaped inner ear, likewise known as the cochlea. The inner hair cells “hairs” flex as a result of the sound waves, providing a signal through the nerves to the brain, which translates the noise we hear.
We have actually thought for the last 100 years that each sensory cell has its own “ideal frequency” (a measure of the number of sound waves per second). This implies that a sensory cell with an optimal frequency of 1000 Hz will react considerably less highly to noises with a little lower or higher frequencies. A research study team has revealed that this is not the case for sensory cells that process low-frequency noise with frequencies less than 1000 Hz.
