Modulating Cerebral Asymmetries for Language

人脑的大脑皮层被细分为左右两个半球，它们以不同的方式处理信息。虽然人们承认，几乎所有的精神活动都需要每个大脑半球做出一些贡献，但理解每个系统何时以及如何参与各种认知任务仍然是一个重大的科学挑战。这项研究的长期目标是确定人们理解单词时左右半球的准确贡献。实验将检验这一假设，即每个大脑半球在单词识别中的相对参与是由单词所经历的语言环境决定的，而不是由单词本身的内在特征决定的。词汇将出现在左侧或右侧视野中，从而选择性地刺激右侧或左侧大脑半球。两个重要的词汇属性将被研究：语法类(名词与动词)和意义的具体性(具体与抽象)。据预测，在动词或抽象词的语境中，右脑对名词和具体词的识别将比在同质语境中做出更大的贡献。这样的发现表明，大脑对单词识别的不对称性随着刺激环境的变化而动态变化，而不是反映静态的(因此是不可改变的)加工差异。这项研究将指出语境在多大程度上调节用于识别单词的大脑系统，从而增强我们对语言理解的神经基础的理解。

The cortex of the human brain is subdivided into two halves, the left and right hemispheres, which process information in characteristically different ways. Although it is acknowledged that nearly all mental activities require some contribution from each cerebral hemisphere, understanding when and how each system participates in a variety of cognitive tasks remains a significant scientific challenge. The long-term goal of this research is to determine the precise contributions of the left and right hemispheres when people comprehend words. The experiments will test the hypothesis that the relative participation of each hemisphere in word recognition is determined by the linguistic context in which a word is experienced, rather than by intrinsic characteristics of the word itself. Words will be presented in the left or right visual fields, thereby selectively stimulating the right or left hemisphere. Two important word properties will be investigated: grammatical class (noun vs verb) and concreteness of meaning (concrete vs abstract). It is predicted that the right cerebral hemisphere will make a greater contribution to recognizing nouns and concrete words in the context of verbs or abstract words, than in more homogeneous contexts. Such findings would suggest that cerebral asymmetries for word recognition vary dynamically in concert with variation in the stimulus environment, rather than reflecting static (and hence unmodifiable) processing differences. This research will indicate the extent to which context modulates the brain systems used to recognize words, thereby enhancing our understanding of the neural bases for language comprehension.