Fwd: AUDITORY Digest - 21 Sep 2004 to 25 Sep 2004 (#2004-199)

Subject: Fwd: AUDITORY Digest - 21 Sep 2004 to 25 Sep 2004 (#2004-199)
From: Kevin Austin (kevin.austin@videotron.ca)
Date: Sun Sep 26 2004 - 00:38:33 EDT




>Date: Sun, 26 Sep 2004 00:00:11 -0400
>From: Automatic digest processor <LISTSERV@LISTS.MCGILL.CA>
>There are 4 messages totalling 226 lines in this issue.
>Topics of the day:
> 1. 'Speak in my right ear and sing in my left' (3)
> 2. 'Speak in my right ear and sing in my left' -- Sininger & Cone-Wesson,
> Science 2004
>Date: Sat, 25 Sep 2004 08:30:14 -0700
>From: hilarleo <hilarleo@UCLINK.BERKELEY.EDU>
>Subject: 'Speak in my right ear and sing in my left'
>"Asymmetric Cochlear Processing Mimics Hemispheric Specialization"
>Described in Science, Vol 305, Issue 5690, 1581 , 10 September 2004
>by Y. S. Sininger and B. Cone-Wesson:
>This finding is similar to those of enhanced processing of tones in
>right auditory cortical areas and of rapidly changing stimuli on the
>left, (given strong crossed connections from ear to brain)...
>Behaviorally, reaction time is faster and stimulus identification is
>more accurate when a subject's right ear is presented with speech-type
>stimuli or when the left ear is presented with tonal information ...
> >These findings indicate that processing at the level of the ear
>may facilitate lateralization of auditory function in the brain...
>"We always assumed that our left and right ears worked exactly the same
>"We were intrigued to discover that clicks triggered more amplification
>in the baby's right ear..."
>Authorial interviews from South African Independent Media Online
>described as
> 'Speak in my right ear and sing in my left'; Full text follows.
><Washington - The right and left human ears process sound differently,
>according to scientists who studied the hearing of babies and found the
>right ear better at picking up speech-like sounds and the left more
>attuned to music.
>It has long been known that the right and left halves of the brain
>process sound differently, but those differences were thought to stem
>from cellular properties unique to each brain hemisphere.
>The new research suggests that the differences start at the ear.
>"We always assumed that our left and right ears worked exactly the same
>way," said lead researcher Yvonne Sininger of the University of
>California at Los Angeles. "As a result, we tended to think it didn't
>matter which ear was impaired in a person. Now we see that it may have
>profound implications for the individual's speech and language
>The discovery, described in the current issue of Science Magazine, will
>help doctors enhance speech and language development in
>hearing-impaired newborns and the rehabilitation of persons with
>hearing loss.
>Sininger and her colleagues studied hearing in more than 3 000
>newborns, specifically tiny amplifiers located in the outer hair cells
>of the inner ear.
>These cells contract and expand to amplify sound vibrations, convert
>the vibrations to neural cells and send them to the brain.
>The scientists inserted tiny probes into the babies' ears that emitted
>two different types of sounds and measured the amplified vibrations.
>They found that speech-like clicks triggered greater amplification in
>the right ear, while music-like sustained tones were more greatly
>amplified by the left ear.
>"We were intrigued to discover that the clicks triggered more
>amplification in the baby's right ear, while the tones induced more
>amplification in the baby's left ear," Sininger said. "This parallels
>how the brain processes speech and music, except the sides are reversed
>due to the brain's cross connections."
>"Our findings demonstrate that auditory processing starts in the ear
>before it is ever seen in the brain," said co-author Barbara
>Cone-Wesson of the University of Arizona. "Even at birth, the ear is
>structured to distinguish between different types of sound and to send
>it to the right place in the brain." - Sapa-AFP >
>1 510 549 0146

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