Functional MR imaging exposes differential brain responses to syntax and prosody during auditory sentence comprehension

Abstract

In two experiments using event-related functional magnetic resonance imaging we studied healthy adults who listened to sentences that either focused on lexical, syntactic, or prosodic information. In the first experiment two sentence conditions were employed: normal speech which contained function and content words, and pseudo speech which contained function and pseudo words. Sentence processing generally activated the superior temporal region (STR) bilaterally. Relative to normal sentences hearing pseudo sentences corresponded to stronger brain responses in the anterior STR (planum polare) and in the fronto-opercular region bilaterally. A second experiment was designed to test whether right hemisphere activation can be explained by processing prosodic aspects of speech, i.e. sentence intonation. In addition to normal and pseudo speech the second study examined degraded speech that neither contained morphosyntactic nor lexical information but only prosodic information, i.e. intonation, amplitude, duration, and spectral tilt. Statistical analyses based on regions of interest found differential activation patterns for frontal and temporal areas in the brain. Relative to sentences, degraded speech produced generally stronger activation in frontal regions. Furthermore, the data pointed to a particular involvement of right fronto-lateral regions in processing sentence melody. For the STR an inverse pattern was found: relative to degraded speech sentence conditions produced stronger activation in anterior, mid, and posterior parts of the left supratemporal plane, particular in the planum polare and planum temporale. In sum, the results show that the left planum polare and the left planum temporale mediate syntactic and semantic processing, whereas right fronto-lateral areas seem to be more sensitive to prosodic cues available in spoken language. q

Selective Attention to Semantic and Syntactic Features Modulates Sentence Processing Networks in Anterior Temporal Cortex

“…Previous research has implicated the anterior temporal cortex in processing speech containing syntactic structure (Mazoyer et al 1993;Humphries et al 2001Humphries et al , 2005Vandenberge et al 2002;Meyer et al 2003). Similarly, in the present study, we found that bilateral ATL regions demonstrated an increased BOLD response while listening to sentences compared with noun lists.…”

“…Broca's area traditionally has been the central focus in investigating these sentence-level processes (Caramazza and Zurif 1976;Linebarger et al 1983;Caplan et al 2000), but more recent work has suggested that Broca's area plays only a limited role in receptive syntax (Grodzinsky 2000). Thus, investigations of syntactic processing have begun to target other cortical regions, particularly the anterior temporal lobe (ATL) (Mazoyer et al 1993;Dronkers et al 1994Dronkers et al , 2004Stowe et al 1999;Humphries et al 2001Humphries et al , 2005Meyer et al 2003). Some of these studies are reviewed below to summarize the known response properties of the ATL during sentence comprehension.…”

The role of the insula in speech and language processing

“…More recently, an fMRI study investigating neural responses to sentences varying in pitch information (normal intonation versus synthesized flattened speech) and syntactic information (normal speech versus synthesized, de-lexicalized speech) found right fronto-lateral activation in response to prosodic cues. The right-superior temporal region and fronto-opercular cortex were identified as being more involved in processing prosodic information (Meyer et al, 2003). These findings suggest that the right hemisphere frontal lobe support prosodic comprehension.…”

The Role of the Insular Cortex in Pitch Pattern Perception: The Effect of Linguistic Contexts

“…Neuroimaging studies of sentence intonation processing have found activation in the frontal operculum extending to the anterior insula (Kotz et al, 2003;Meyer et al, 2003). Magnetoencephalography studies have observed a right-lateralized frontal region to be associated with nonlexical intonation processing (Herrmann et al, 2003).…”