Department of Psychology and Institute for Learning and Brain Sciences, University of Washington, Seattle, WA 98195-1525, USA.
Cereb Cortex. 2011 Aug;21(8):1747-60. doi: 10.1093/cercor/bhq241. Epub 2010 Dec 10.
This study used functional magnetic resonance imaging to investigate individual differences in the neural underpinnings of sentence comprehension, with a focus on neural adaptability (dynamic configuration of neural networks with changing task demands). Twenty-seven undergraduates, with varying working memory capacities and vocabularies, read sentences that were either syntactically simple or complex under conditions of varying extrinsic working memory demands (sentences alone or preceded by to-be-remembered words or nonwords). All readers showed greater neural adaptability when extrinsic working memory demands were low, suggesting that adaptability is related to resource availability. Higher capacity readers showed greater neural adaptability (greater increase in activation with increasing syntactic complexity) across conditions than did lower capacity readers. Higher capacity readers also showed better maintenance of or increase in synchronization of activation between brain regions as tasks became more demanding. Larger vocabulary was associated with more efficient use of cortical resources (reduced activation in frontal regions) in all conditions but was not associated with greater neural adaptability or synchronization. The distinct characterizations of verbal working memory capacity and vocabulary suggest that dynamic facets of brain function such as adaptability and synchronization may underlie individual differences in more general information processing abilities, whereas neural efficiency may more specifically reflect individual differences in language experience.
本研究采用功能磁共振成像技术，探讨了句子理解的神经基础的个体差异，重点是神经适应性（随着任务需求的变化，神经网络的动态配置）。27 名大学生，具有不同的工作记忆容量和词汇量，在不同的外在工作记忆需求条件下（句子本身或在要记住的单词或非单词之前）阅读句法简单或复杂的句子。当外在工作记忆需求较低时，所有读者都表现出更大的神经适应性，这表明适应性与资源可用性有关。与低容量读者相比，高容量读者在所有条件下表现出更大的神经适应性（随着句法复杂度的增加，激活的增加更大）。高容量读者还表现出随着任务变得更加困难，大脑区域之间的激活同步性更好的维持或增加。较大的词汇量与所有条件下皮质资源的更有效利用（额叶区域的激活减少）相关，但与更大的神经适应性或同步性无关。言语工作记忆容量和词汇量的不同特征表明，大脑功能的动态方面，如适应性和同步性，可能是更一般信息处理能力个体差异的基础，而神经效率可能更具体地反映语言经验的个体差异。
