ABSTRACT

The quality of language that children hear in their environment is associated with the development of language-related brain regions, in turn promoting vocabulary knowledge. Although informative, it remains unknown how these environmental influences alter the structure of neural tissue and subsequent vocabulary outcomes. The current study uses magnetic resonance elastography (MRE) to examine how children’s language environments underlie brain tissue mechanical properties, characterized as brain tissue stiffness and damping ratio, and promote vocabulary knowledge. Twenty-five children, ages 5–7, had their audio and video recorded while engaging in a play session with their parents. Children also completed the Picture Vocabulary Task (from NIH Toolbox) and participated in an MRI, where MRE and anatomical images were acquired. Higher quality input was associated with greater stiffness in the bilateral inferior frontal gyrus and right superior temporal gyrus, whereas greater vocabulary knowledge was associated with lower damping ratio in the right inferior frontal gyrus. These findings suggest changes in neural tissue composition are sensitive to malleable aspects of the environment, whereas tissue organization is more strongly associated with vocabulary outcome. Notably, these associations were independent of maternal education, suggesting more proximal measures of a child’s environment may be the source of differences in neural tissue structure underlying variability in vocabulary outcomes.

摘要

儿童在环境中听到的语言质量与语言相关大脑区域的发育有关，进而促进词汇知识的发展。尽管信息丰富，但这些环境影响如何改变神经组织的结构和随后的词汇结果仍然未知。目前的研究使用磁共振弹性成像（MRE）来检查儿童的语言环境如何影响脑组织的机械特性（以脑组织的硬度和阻尼比为特征），并促进词汇知识的积累。25 名 5 至 7 岁的孩子在与父母一起玩耍时，被录制了音频和视频。孩子们还完成了图片词汇任务（来自 NIH 工具箱）并参加了 MRI，其中获取了 MRE 和解剖图像。更高质量的输入与双侧额下回和右颞上回更大的刚度相关，而更多的词汇知识与右额下回更低的阻尼比相关。这些发现表明，神经组织组成的变化对环境的可塑性方面敏感，而组织组织与词汇结果的相关性更强。值得注意的是，这些关联与母亲教育无关，这表明对儿童环境的更近端测量可能是词汇结果变异性背后神经组织结构差异的根源。