Towards a functional neuroanatomy of speech perception

The functional neuroanatomy of speech perception has been difficult to char acterize. Part of the difficulty, we suggest, stems from the fact that the neural systems supporting 'speech perception' vary as a function of the tas k. Specifically, the set of cognitive and neural systems involved in perfor ming traditional laboratory speech perception tasks, such as syllable discr imination or identification, only partially overlap those involved in speec h perception as it occurs during natural language comprehension. In this re view, we argue that cortical fields in the posterior-superior temporal lobe , bilaterally, constitute the primary substrate for constructing sound-base d representations of speech, and that these sound-based representations int erface with different supramodal systems in a task-dependent manner. Tasks that require access to the mental lexicon (i.e. accessing meaning-based rep resentations) rely on auditory-to-meaning interface systems in the cortex i n the vicinity of the left temporal-parietal-occipital junction. Tasks that require explicit access to speech segments rely on auditory-motor interfac e systems in the left frontal and parietal lobes. this auditory-motor inter face system also appears to be recruited in phonological working memory.