[lingtalks] TIME UPDATE: Stephen Wilson 4/30 (Linguistics Colloquium)

[Klinton Bicknell]

This talk will start promptly at 2:00pm, or slightly before, to mitigate
overlap between this talk and Josh Tenenbaum's 3:15 talk.


---------------------------- Original Message ----------------------------
Subject: Fwd: [lingtalks] Stephen Wilson 4/30 (Linguistics Colloquium)
From:    "hannah rohde" <hannah at ling.ucsd.edu>
Date:    Sat, April 28, 2007 12:28 am
To:      "Klinton Bicknell" <kbicknell at ucsd.edu>
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On Monday 30 April at 2pm, Stephen Wilson (UC-Irvine;
http://lcbr.ss.uci.edu/wilson/) will give a colloquium at the UCSD
Linguistics Department, in AP&M 4301.

:: Abstract ::

Neuroimaging studies of the role of speech motor areas in speech
perception
Stephen M. Wilson, UC-Irvine

The role of superior temporal cortex in speech perception is well
established, but there is also much evidence suggestive of an ancillary
role for frontal speech motor areas in the perceptual process. A series
of studies using functional magnetic resonance imaging (fMRI) and
transcranial magnetic stimulation (TMS) will be presented in support of
this idea. In the first study, subjects listened passively to
monosyllables, and produced the same speech sounds. Listening to speech
activated a premotor cortical region largely overlapping a speech
production motor area centered just posteriorly. These findings support
the view that the motor system is recruited in mapping the acoustic
signal to a phonetic code. The next study examined neural responses to
unfamiliar non-native phonemes varying in the extent to which they can
be articulated. Both superior temporal (auditory) and precentral (motor)
areas were activated by passive speech perception, and both
distinguished non-native from native phonemes. Furthermore,
speech-responsive motor regions and superior temporal sites were
functionally connected. However, only in auditory areas did activity
covary with the producibility of non-native phonemes. These data suggest
that auditory areas are crucial for the transformation from acoustic
signal to phonetic code, but the motor system also plays an active role,
perhaps in generating candidate phonemic categorizations. A third study
aimed to determine whether speech motor regions are crucial for speech
perception or merely coactivated. We used repetitive TMS to create a
“virtual lesion” in left premotor cortex while subjects performed a
speech perception task and a matched color perception task. Performance
was disrupted on the speech perception task, but not on the control
task, suggesting that this speech motor region is in fact necessary for
speech perception. In sum, these studies motivate an important role for
speech motor areas in the perception of speech.

--

For further information about the Linguistics department colloquia
series, including the schedule of future events, please visit
http://ling.ucsd.edu/events/colloquia.html .
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