A team of University of Oregon researchers have isolated an independent processing channel of synapses inside the brain's auditory cortex that deals specifically with shutting off sound processing at appropriate times. Such regulation is vital for hearing and for understanding speech.
The discovery, detailed in the Feb. 11 issue of the journal Neuron, goes against a long-held assumption that the signaling of a sound's appearance and its subsequent disappearance are both handled by the same pathway. The new finding, which supports an emerging theory that a separate set of synapses is responsible, could lead to new, distinctly targeted therapies such as improved hearing devices, said Michael Wehr, a professor of psychology and member of the UO Institute of Neuroscience.
"It looks like there is a whole separate channel that goes all the way from the ear up to the brain that is specialized to process sound offsets," Wehr said. The two channels finally come together in a brain region called the auditory cortex, situated in the temporal lobe.
To do the research, Wehr and two UO undergraduate students -- lead author Ben Scholl, now a graduate student at the Oregon Health and Science University in Portland, and Xiang Gao -- monitored the activity of neurons and their connecting synapses as rats were exposed to millisecond bursts of tones, looking at the responses to both the start and end of a sound. They tested varying lengths and frequencies of sounds in a series of experiments.It became clear, the researchers found, that one set of synapses responded "very strongly at the onset of sounds," but a different set of synapses responded to the sudden disappearance of sounds. There was no overlap of the two responding sets, the researchers noted. The end of one sound did not affect the response to a new sound, thus reinforcing the idea of separate processing channels.
"Being able to perceive when sound stops is very important for speech processing," Wehr said. "One of the really hard problems in speech is finding the boundaries between the different parts of words. It is really not well understood how the brain does that."
As an example, he noted the difficulty some people have when they are at a noisy cocktail party and are trying to follow one conversation amid competing background noises. "We think that we've discovered brain mechanisms that are important in finding the necessary boundaries between words that help to allow for successful speech recognition and hearing," he said.
The research -- funded in part by the UO's Robert and Beverly Lewis Center for Neuroimaging Fund -- aims to provide a general understanding of how areas of the brain function. The new findings, Wehr said, could also prove useful in working with children who have deficits in speech and learning, as well as in the design of hearing aids and cochlear implants. He also noted that people with dyslexia have problems defining the boundaries of sounds in speech, and tapping these processing areas in therapy could boost reading skills.
About the University of Oregon
The University of Oregon is a world-class teaching and research institution and Oregon's flagship public university. The UO is a member of the Association of American Universities (AAU), an organization made up of the 62 leading public and private research institutions in the United States and Canada. The UO is one of only two AAU members in the Pacific Northwest.
Source: Michael Wehr, assistant professor of psychology, 541- 346-5866, firstname.lastname@example.org
Links:Wehr faculty page: http://psychweb.uoregon.edu/people/wehr-michael
Jim Barlow | EurekAlert!
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences