Developmental differences of neurocognitive networks for phonological and semantic processing in Chinese word reading

Abstract

Developmental differences in the neurocognitive networks for phonological and semantic processing in Chinese word reading were examined in 13 adults and 13 children using functional magnetic resonance imaging (fMRI). Rhyming and semantic association judgments were made to two-character words that were presented sequentially in the visual modality. These lexical tasks were compared with a nonlinguistic control task involving judgment of line patterns. The first main finding was that adults showed greater activation than children in right middle occipital gyrus on both the meaning and rhyming task, suggesting adults more effectively engage right hemisphere brain regions involved in the visual-spatial analysis of Chinese characters. The second main finding was that adults showed greater activation than children in left inferior parietal lobule for the rhyming as compared with the meaning task, suggesting greater specialization of phonological processing in adults. The third main finding was that children who had better performance in the rhyming task on characters with conflicting orthographic and phonological information relative to characters with nonconflicting information showed greater activation in left middle frontal gyrus, suggesting greater engagement of brain regions involved in the integration of orthography and phonology.

Figure 1

Examples of Chinese stimuli used for the rhyming tasks with their English interpretation and their pronunciation in pinyin. Numbers for the pinyin translations indicate tone. There are four different tones including the high‐level tone (first tone), the rising tone (second tone), the falling rising tone (third tone), and the falling tone (fourth tone).

Figure 2

Examples of Chinese stimuli used for the meaning tasks with their English interpretation and their pronunciation in pinyin. See Figure 1 caption.

Figure 3

Main effects for children and adults. Brain activations for the meaning versus control trials (Panel a) and rhyming versus control trials (Panel b) in children (green) and in adults (red). Overlap between groups is represented in blue. For meaning versus control and rhyming versus control, both children and adults showed activation in left middle frontal gyrus (MFG), left inferior frontal gyrus (IFG), left fusiform gyrus (FG), and right middle occipital gyrus (MOG). For meaning versus control, both children and adults additionally showed activation in left middletemporal gyrus (MTG). See Table IV for a full listing of activations. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Figure 4

Developmental differences in brain activation. (a) Greater activation for adults than for children in rhyming versus meaning using control as a baseline in left inferior parietal lobule (IPL). (b) Greater activation for adults than for children in rhyming versus control (red) and meaning versus control (green) in right middle occipital gyrus (MOG). Overlap between these two contrasts is in blue. See Table V for a full listing of activations. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Figure 5

Brain‐behavior correlations for children. (a) Negative correlations of the difference in accuracy between nonconflicting and conflicting trials in rhyming judgment with activation in the rhyming minus control contrast in left middle frontal gyrus (MFG) and bilateral precuneus (Prec). (b) Positive correlations of the difference in accuracy between nonconflicting and conflicting trials in rhyming judgment with activation in the rhyming minus control contrast in bilateral anterior cingulate gyrus (AC). (c) Negative correlation of the difference in accuracy between high‐association and low‐association trials in meaning judgment with activation in the meaning minus control contrast in left fusiform gyrus (FG). Positive correlations indicate that larger difference scores for accuracy are correlated with greater activation and negative correlations indicate that smaller difference scores for accuracy are correlated with greater activation. See Table VI for a full listing of activations. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]