Neural signatures of lexical tone reading

Abstract

Research on how lexical tone is neuroanatomically represented in the human brain is central to our understanding of cortical regions subserving language. Past studies have exclusively focused on tone perception of the spoken language, and little is known as to the lexical tone processing in reading visual words and its associated brain mechanisms. In this study, we performed two experiments to identify neural substrates in Chinese tone reading. First, we used a tone judgment paradigm to investigate tone processing of visually presented Chinese characters. We found that, relative to baseline, tone perception of printed Chinese characters were mediated by strong brain activation in bilateral frontal regions, left inferior parietal lobule, left posterior middle/medial temporal gyrus, left inferior temporal region, bilateral visual systems, and cerebellum. Surprisingly, no activation was found in superior temporal regions, brain sites well known for speech tone processing. In activation likelihood estimation (ALE) meta-analysis to combine results of relevant published studies, we attempted to elucidate whether the left temporal cortex activities identified in Experiment one is consistent with those found in previous studies of auditory lexical tone perception. ALE results showed that only the left superior temporal gyrus and putamen were critical in auditory lexical tone processing. These findings suggest that activation in the superior temporal cortex associated with lexical tone perception is modality-dependent.

The dynamic nature of assimilation and accommodation procedures in the brains of Chinese–English and English–Chinese bilinguals

“…Our findings are consistent with two previous studies suggesting that high L2 proficiency in late English-Chinese bilinguals was associated with increased brain activation in the Chinese network (e.g., accommodation) [Cao et al, 2013b;Deng et al, 2011]. The right IFG has been suggested as playing an important role in Chinese lexical tone processing [Kwok et al, 2015;Liu et al, 2006], thus the positive correlation in this region in EC with L2 proficiency may indicate that English speakers with higher L2 (Chinese) proficiency may make greater use of the Chinese lexical tone processing region in their r Neural Mechanisms in Second Language Reading r r 4155 r L2 reading. The dorsal aspect of left IPL has been suggested to play a specific role of short-term storage of phonological information of Chinese characters because the processing of Chinese characters' phonology is not based on rules but instead relies on a direct retrieval procedure from rote memory, and this may obligate readers to maintain phonological codes for a short-term to accomplish the required tasks [Tan et al, 2005].…”

Neural correlates and functional connectivity of lexical tone processing in reading

“…We also did not observe any connections between the STG and other voxels within the brain in our lexical tone dis-crimination task. Thus, our findings are consistent with Kwok et al (2015) that the role of superior temporal gyrus in lexical tone perception depends on the input modality. A potential limitation of the current study is that some process differences might be involved in lexical tone judgment vs. font size judgments of characters.…”

“…Activation was also found in the left inferior Stereotaxic coordinates (mm) are derived from the human brain atlas of Talairach and Tournoux (1998) and refer to the peak Z scores for each region (P < 0.05, FDR-corrected) at voxel level for multiple comparisons. selected regions were also previously identified in lexical tone processing in reading (Kwok et al, 2015).…”

“…Our previous work used fMRI to demonstrate the neural signatures of lexical tone processing in Chinese reading (Kwok et al, 2015). Participants were required to judge whether the monosyllabic character presented on each trial carried the high-falling tone, where the baseline condition was an arrow direction judgment asking participants to indicate whether the arrow pointed upward or downward.…”

“…Peak activation in the SMA also reflected participants' effort in auditory imagery (Lima, Krishnan, & Scott, 2016;Tian, Zarate, & Poeppel, 2016), a process in retrieving tonal information of the characters without the presence of auditory stimuli. Activation in the left inferior parietal lobule was frequently found in language tasks, such as orthography-to-phonology transformation (Bitan et al, 2007;Booth et al, 2006;, phonological processing of auditory and visual inputs (Booth et al, 2006;Deschamps, Baum, & Gracco, 2014;Liu et al, 2009;Seghier et al, 2004;Sliwinska, Khadilkar, Campbell-Ratcliffe, Quevenco, & Devlin, 2012;Tan et al, 2003, Tan, Laird, Li, & Fox, 2005, and lexical tone judgment Kwok et al, 2015;Li et al, 2003). Some have considered the inferior parietal region as part of the phonological loop (Cohen et al, 1997;Paulesu, Frith, & Frackowiak, 1993).…”