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Abstract:
Abstract: The functional neuroanatomy of speech perception
has been difficult to characterize. Part of the difficulty, we
suggest, stems from the fact that the neural systems supporting
"speech perception" vary as a function of task. Specifically, the
set of cognitive and neural systems involved in performing
traditional laboratory speech perception tasks, such as
discrimination or identification, are not necessarily the same as
those involved in speech perception as it occurs during natural
language comprehension. Based on a review of data from a range of
methodological approaches, we propose that auditory cortical fields
in the posterior half of the superior temporal lobe, bilaterally,
constitute the primary substrate for constructing sound-based
representations of speech, and that these sound-based
representations interface with different supramodal systems in a
task dependent manner. Tasks which require access to the mental
lexicon (i.e., accessing meaning-based representations) rely on
auditory-to-meaning interface systems in cortex in the vicinity of
the left temporal-parietal-occipital junction; tasks which require
explicit access to speech segments rely on auditory-motor interface
systems in the left frontal and parietal lobes. The left
frontal-parietal auditory-motor interface system also plays an
important role in phonological working memory. NIH DC-0361 (GH),
the McDonnell-Pew program, the NSF LIS initiative, and the
University of Maryland Center of Comparative Neuroscience
(DP).
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