Common and Distinct Neural Substrates for Pragmatic, Semantic, and Syntactic Processing of Spoken Sentences: An fMRI Study

Abstract

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 neuroanatomical substrates? We addressed this issue using functional magnetic resonance imaging (fMRI) to measure neural activity when subjects listened to spoken normal sentences contrasted with sentences that had either (A) pragmatical, (B) semantic (selection restriction), or (C) syntactic (subcategorical) violations sentences. All three contrasts revealed robust activation of the left-inferior-temporal/fusiform gyrus. Activity in this area was also observed in a combined analysis of all three experiments, suggesting that it was modulated by all three types of linguistic violation. Planned statistical comparisons between the three experiments revealed (1) a greater difference between conditions in activation of the left-superior-temporal gyrus for the pragmatic experiment than the semantic/syntactic experiments; (2) a greater difference between conditions in activation of the right-superior and middle-temporal gyrus in the semantic experiment than in the syntactic experiment; and (3) no regions activated to a greater degree in the syntactic experiment than in the semantic experiment. These data show that, while left- 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 types of linguistic information. We suggest that this region may play a key role in using pragmatic, semantic (selection restriction), and subcategorical information to construct a higher representation of meaning of sentences.

FMRI reveals brain regions mediating slow prosodic modulations in spoken sentences

“…This finding is in general accordance with recent neuroimaging studies on the processing of spoken words [Binder et al, 2000;Mazoyer et al, 1993] and sentences [Dehaene et al, 1997;Kuperberg et al, 2000;Meyer et al, 2000;Mü ller et al, 1997;Schlosser et al, 1998] that demonstrated activation in anterior and posterior divisions of the STR. In accordance with the predictions, however, the functional activation in the STR varied as a function of intelligibility.…”

“…Conversely, functional activation in the left and right STR is significantly increased for normal and syntactic speech indicating that grammatical processing during auditory sentence presentation is supported by the STR of both the left and the right hemisphere. This result is in general agreement with recent neuroimaging studies associating auditory sentence comprehension with an involvement of the bilateral STR with the left hemisphere playing a dominant role in right-handed subjects [Kuperberg et al, 2000;Mü ller et al, 1997;Schlosser et al, 1998]. In particular, the (left) anterior STR was shown to play an essential role in processing constituent structures, i.e., general syntactic operations at the sentence-level [Friederici et al, 2000b;Humphries et al, 2001;Meyer et al, 2000;Scott et al, 2000].…”

“…In a number of recent brain imaging studies the auditory processing of normal sentences occurred quite automatically in the STR bilaterally, with only marginal or no activation in Broca's area [Dehaene et al, 1997;Kuperberg et al, 2000;Meyer et al, 2000;Mü ller et al, 1997;Schlosser et al, 1998]. In a recent fMRI study the bilateral inferior frontal cortex, however, subserved processing of syntactic speech, focusing on syntactic and prosodic information in the absence of lexical information [Friederici et al, 2000a].…”

“…From these studies an inconsistent picture has emerged. Listening to normal sentences occurs automatically, thereby recruiting the superior temporal region bilaterally, and relegating the inferior frontal cortex to a minor role [Dehaene et al, 1997;Friederici et al, 2000a;Kuperberg et al, 2000;Meyer et al, 2000;Mü ller et al, 1997;Schlosser et al, 1998]. Studies explicitly focusing on the processing of syntactic information during sentence comprehension, however, report selective activation in left fronto-lateral and fronto-opercular cortices [Caplan et al, 1998;Dapretto and Bookheimer, 1999;Friederici et al, 2000a].…”

Neural substrates of narrative comprehension and memory

“…At least one previous study that directly contrasted narrative-level and sentencelevel comprehension found narrative-specific activation in regions such as ATL, posterior MTG, and DMPFC (Xu et al, 2005). However, other studies have observed greater activation in most of these regions when reading or hearing coherent sentences than random word lists (Bottini et al, 1994;Kuperberg et al, 2000;Stowe et al, 1999;Vandenberghe et al, 2002), suggesting that the difference between narrative-and sentence-level comprehension may be quantitative and not qualitative. Alternatively, narrativespecificity may arise at a hemispheric rather than at a regional level.…”