Common and distinct neural substrates for pragmatic, semantic, and syntactic processing of spoken sentences: an fMRI study

Extracting meaning from speech requires the use of pragmatic, semantic, and syntactic information. A central question is: Does the processing of these different types of linguistic information have common or distinct neuroana tomical substrates? We addressed this issue using functional magnetic reson ance imaging (fMRI) to measure neural activity when subjects listened to sp oken normal sentences contrasted with sentences that had either (A) pragmat ical, (B) semantic (selection restriction), or (C) syntactic (subcategorica l) violations sentences. All three contrasts revealed robust activation of the left-inferior-temporal/fusiform gyrus. Activity in this area was also o bserved in a combined analysis of all three experiments, suggesting that it was modulated by all three types of linguistic violation. Planned statisti cal comparisons between the three experiments revealed (1) a greater differ ence between conditions in activation of the left-superior-temporal gyrus f or the pragmatic experiment than the semantic/syntactic experiments; (2) a greater difference between conditions in activation of the right-superior a nd middle-temporal gyrus in the semantic experiment than in the syntactic e xperiment; and (3) no regions activated to a greater degree in the syntacti c experiment than in the semantic experiment. These data show that, while l eft- and right-superior-temporal regions may be differentially involved in processing pragmatic and lexico-semantic information within sentences, the left-inferior-temporal/fusiform gyrus is involved in processing all three t ypes of linguistic information. We suggest that this region may play a key role in using pragmatic, semantic (selection restriction), and subcategoric al information to construct a higher representation of meaning of sentences .