Trends in Cognitive Sciences
ReviewTowards a functional neuroanatomy of speech perception
Section snippets
Speech perception subserving access to the mental lexicon
This section examines the functional neuroanatomy of speech perception primarily from the perspective of auditory comprehension tasks. Data from auditory comprehension tasks are relevant to the study of speech perception because a prerequisite of auditory comprehension is the construction of a sound-based representation of the speech input which is suitable for making contact with the mental lexicon. Thus, speech perception is one stage in the process of auditory comprehension. Although it is
Speech perception in tasks requiring explicit attention to phonetic structure
We have argued that the primary substrate for constructing sound-based representations of speech comprises auditory related cortices in the posterior superior temporal lobe bilaterally. Much of this argument was based on evidence from tasks that involve auditory comprehension. A glance at the literature on the functional neuroanatomy of speech perception, however, will reveal evidence suggesting that extra-auditory cortical regions play an important role in receptive phonetic processing. For
Conclusions
In this review we have argued: (1) that the posterior–superior temporal lobe bilaterally constitutes the primary cortical substrate for the construction of sound-based representations of speech; (2) that while both hemispheres participate, they probably make different contributions to speech perception (Box 1); (3) that left hemisphere frontal and parietal regions, sometimes implicated in aspects of speech perception (and also in phonological working memory), may be understood in terms of a
Outstanding questions
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We have proposed that superior temporal lobe structures play an important role in constructing ‘sound-based representations of speech.’ This process is complex, probably involving multiple levels of representation. How does this general notion of sound-based representations map onto the different linguistic levels of representation (e.g. phonetic features, syllabic structure, etc.)? Are there neuroanatomical subdivisions within auditory cortex that correspond to these levels of representation?
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Acknowledgements
The work was supported by NIH DC-0361 (to G.H.), the McDonnell-Pew program, the National Science Foundation LIS initiative, and the University of Maryland Center of Comparative Neuroscience (to D.P.).
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