Tu Liu, Zhou Fangyuan, Omata Kei, Li Wendi, Huang Ruiwang, Gao Wei, Zhu Zhenzhen, Li Yanyan, Liu Chang, Mao Mengying, Zhang Shuyu, Hanakawa Takashi
College of Foreign Studies, Jinan University, Guangzhou, China.
Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Kodaira, Japan.
Front Psychol. 2022 Apr 25;13:824219. doi: 10.3389/fpsyg.2022.824219. eCollection 2022.
It is interesting to explore the effects of second language (L2) acquisition on anatomical change in brain at different stages for the neural structural adaptations are dynamic. Short-term Chinese training effects on brain anatomical structures in alphabetic language speakers have been already studied. However, little is known about the adaptations of the gray matter induced by acquiring Chinese language for a relatively long learning period in adult alphabetic language speakers. To explore this issue, we recruited 38 Indian overseas students in China as our subjects. The learned group included 17 participants who had learned Mandarin Chinese for an average of 3.24 years and achieved intermediate Chinese language proficiency. The control group included 21 subjects who had no knowledge about Chinese. None of the participants had any experience in learning logographic and tonal language before Chinese learning. We found that (1) the learned group had significantly greater gray matter volume (GMV) in the left lingual gyrus (LG) compared with the control group; (2) the Chinese characters' reading accuracy was significantly and positively correlated to the GMV in the left LG and fusiform gyrus (FG) across the two groups; and (3) in the learned group, the duration of Chinese learning was significantly and positively correlated with the GMV in the left inferior frontal gyrus (IFG) after correction for multiple comparisons with small volume corrections. Our structural imaging findings are in line with the functional imaging studies reporting increased brain activation induced by Chinese acquisition in alphabetic language speakers. The regional gray matter changes reflected the additional requirements imposed by the more difficult processing of Chinese characters and tones. The present study also show that the biological bases of the adaptations induced by a relatively long period of Chinese learning were limited in the common areas for first and foreign language processing.
探索第二语言（L2）习得在不同阶段对大脑解剖结构变化的影响很有趣，因为神经结构适应是动态的。已经有关于短期中文训练对字母语言使用者大脑解剖结构影响的研究。然而，对于成年字母语言使用者在相对较长学习期习得中文所引起的灰质适应性变化却知之甚少。为了探究这个问题，我们招募了38名在中国的印度留学生作为研究对象。学习组包括17名参与者，他们平均学习普通话3.24年，达到中文中级水平。对照组包括21名对中文一无所知的受试者。所有参与者在学习中文之前都没有学习过表意文字和声调语言的经历。我们发现：（1）与对照组相比，学习组左侧舌回（LG）的灰质体积（GMV）显著更大；（2）两组中汉字阅读准确性与左侧LG和梭状回（FG）的GMV均呈显著正相关；（3）在学习组中，经过小体积校正的多重比较校正后，中文学习时长与左侧额下回（IFG）的GMV显著正相关。我们的结构成像结果与功能成像研究一致，后者报告了字母语言使用者习得中文所引起的大脑激活增加。区域灰质变化反映了处理汉字和声调更困难所带来的额外需求。本研究还表明，相对较长时间的中文学习所引起的适应性变化的生物学基础局限于第一语言和外语处理的共同区域。
