Neural and psychological correlates of phonological categories

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Understanding language results from a very efficient decoding of the speech signal along the auditory pathway to associative structures in long-term memory. The path between sound and meaning is mediated by different types of representation. Some of these code gradient information from speech input (phonetic representations), but some are discrete and abstract, such as phonological categories, onto which speech also must be mapped. In this project, we will try to decipher the nature of these representations by (1) monitoring their activation by means of early neural responses with MEG and by (2) assessing the brain substrate subserving such representations with MEG and fMRI. Two main representations are focused upon: phonemic and syllabic categories. Phonemic and/or (sub)syllabic representations will be probed for (a) their fit with information in the speech input, in relation to underspecification of segments and of adjacent speech context; (b) their sensitivity to combined auditory and visual speech information; (c) the plasticity and flexibility of the representational system as assessed by training and learning, and (d) the neural substrate involved in processing and representation of existing and newly learned tokens within phonemic and syllabic categories.