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September 2007
While the visual regions of the brain have been
intensively mapped, many important regions for auditory processing remain
"uncharted territory." Now, researchers at the Hebrew University of
Jerusalem and elsewhere have identified a region responsible for a key
auditory process-perceiving "sound space," the location of sounds, even
when the listener is not concentrating on those sounds. The findings
settle a controversy in earlier studies that failed to establish the
auditory region, called the planum temporale, as responsible for
perception of auditory space by default.
Full Story
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September 2007
On September 19, a research report by Helsinki
University of Technology, Laboratory of Computational Engineering
scientists appeared in the online, open-access journal PLoS ONE (Public
Library of Science), showing that selective attention increases both gain
and feature selectivity of the human auditory cortex. The ability to
select task-relevant sounds for awareness, while ignoring irrelevant ones,
constitutes one of the most fundamental of human faculties, but the
underlying neural mechanisms have remained elusive. While most of the
literature explains the neural basis of selective attention by means of an
increase in neural gain, a number of papers propose enhancement in neural
selectivity as an alternative or a complementary mechanism.
Full
Story
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October 2007
There is very little knowledge about
alcohol-induced hearing loss. Alcohol consumption and tolerance to loud
noise is a well observed phenomenon as seen in the Western world where
parties get noisier by the hour as the evening matures. This leads to
increase in the referrals to the "hearing aid clinic" and the diagnosis of
"cocktail party deafness" which may not necessarily be only due to
presbyacusis or noise-induced hearing loss.
Full Story
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October 2007
The mosquito is no longer just a blood-sucking
pest -- it is also the name of an ultra-sonic teenage deterrent system
that is being introduced to the Regina market. Using a high-frequency
tone, the device annoys youths and deters them from loitering and being in
its general vicinity within minutes of activation. It has been used in the
United Kingdom since 2005 and is now being implemented in Canadian
markets, such as Vancouver, and it might make its debut in Saskatchewan
very soon. "It is currently being used at convenience stores, schools,
pubs, and malls," Michael Gibson of Moving Sound Technologies said Friday
from Vancouver. "Store owners are using the devices to get kids that are
hanging out in front of stores and (hurting business) to leave the
storefront." Gibson said his company has installed these devices in four
locations of a large convenience store chain in Vancouver and Victoria
that had unwanted traffic. He said store patrons simply weren't going into
the store because they didn't want to encounter unwanted people hanging
around outside.
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November 2007
New research indicates that non-nerve cells play a
critical role in stimulating auditory nerve firing in the absence of
sound, in preparation for the development of hearing. "It was known that
this 'spontaneous' activity helps auditory nerves make proper connections
with other nerve cells in the brain, which enables the accurate encoding
of sound; however, the trigger that initiates this activity was not
known," senior author Dr. Dwight E. Bergles told Reuters Health. "We
discovered that non-nerve cells in the developing inner ear stimulate
electrical activity in nerves that carry sound information from the ear to
the brain." Dr. Bergles, from the Johns Hopkins School of Medicine in
Baltimore, said the discovery that non-nerve cells were involved in the
initial stimulatory activity was particularly surprising since it had been
thought that these cells were merely bystanders.
Full Story
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December 2007
While neurotrophins have historically been prized
for the survival value they impart to nerve cells, the researchers found
that in the cochlea they do a great deal more. Their presence in relative
proportions transforms the spiral ganglion neurons into either fast-firing
transmitters to carry high-pitched sound messages to the brain, or
slow-firing carriers for the transmission of lower pitched signals. The
neurotrophins accomplish this at the molecular level by tightly regulating
a newly defined and complex series of signaling proteins. Davis explained
that one end of the cochlea is home to the slower-firing neurons
characterized by a preponderance of NT-3, while the other cochlear end is
rich in BDNF, making those neurons faster-firing. Both neurotrophins are
present in gradients throughout the range, but at any specific locale
their amounts vary relative to each other - lots of BDNF and a little NT-3
in the high frequency transmitters, for example, and the reverse as you
move toward the other end.
Full Story
