Poster C19, Friday, August 17, 10:30 am – 12:15 pm, Room 2000AB
Syntactic and semantic specialization in 5-6 year-old children during auditory sentence processing
Jin Wang1, Mable Rice2, James Booth1;1Psychology and Human Development Department, Vanderbilt University, 2College of Liberal Arts and Sciences-Speech-Language-Hearing, The University of Kansas
Previous studies have found specialized syntactic and semantic processes in the adult brain during language comprehension. The left inferior frontal gyrus (IFG) opercularis and posterior superior temporal gyrus (STG) were found to be associated with syntactic processing, whereas the left inferior frontal gyrus (IFG) triangularis and middle temporal gyrus (MTG) were found to be associated with semantic processing (Price, 2012; Frederici, 2012). However, it remains an open question when syntactic and semantic specialization emerges in the developing brain. 5-6-year-old children have obtained sophisticated semantic and syntactic aspects of language, so they should show specialization in these processes. Yet many previous functional magnetic resonance imaging (fMRI) studies on 5-6-year-old children failed to detect this specialization, possibly due to the experimental design and analytical methods. Most of these studies used anomalous sentences that were likely to intermix syntactic and semantic processes. Moreover, all studies used univariate analysis which may be insensitive to subtle differences in the brain because they average across voxels. In current fMRI study, we designed a syntactic task and a semantic task to dissociate these two processes. Twenty-nine participants from 5.6-6.5 years old completed both tasks. The syntactic task included four conditions: plurality violation, finiteness violation, grammatically correct and perceptual control conditions. Participants were asked to make a grammatical judgment, i.e. “does the way she speaks sound right”. The semantic task also included four conditions: strongly congruent, weakly congruent, incongruent, and perceptual control conditions. Participants were asked to make a plausibility judgement, i.e. “does the way she speaks make sense”. In addition to conventional univariate analysis, Representational Similarity Analysis (RSA) was used to examine the correlation of patterns within a task (between runs) versus across tasks. Only grammatically correct and strongly congruent sentences were used in the analysis because they both required a yes response, allowing us to examine normal sentence comprehension processes. Consistent with previous studies using univariate analyses, we only found the opercularis portion of left inferior frontal gyrus (IFG) was significantly activated in the syntactic task compared to semantic task, but no area was found in the reverse contrast. However, we found a double dissociation by using RSA analysis, where the left opercularis IFG and superior temporal gyrus (STG) showed more similar patterns within the syntactic task compared to across tasks, whereas there was no difference in the correlations within the semantic task compared to across task in these regions. In contrast, the left triangularis IFG and middle temporal gyrus (MTG) showed more similar patterns within the semantic task compared to across tasks, whereas there was no (smaller) difference in the correlation within the syntactic task compared to across task in these regions. These results suggest that 5-6-year-old children have already started to show semantic and syntactic specialization in the brain. This study has implications for neurocognitive models of language comprehension and developmental language disorder.
Topic Area: Grammar: Syntax