Recent neuroimaging research has suggested that unequal cognitive efforts exist between interpreting from language 1 (L1) to language 2 (L2) compared with interpreting from L2 to L1. However, the neural substrates that underlie this directionality effect are not yet well understood. Whether directionality is modulated by interpreting expertise also remains unknown. In this study, we recruited two groups of Mandarin (L1)/English (L2) bilingual speakers with varying levels of interpreting expertise and asked them to perform interpreting and reading tasks. Functional near-infrared spectroscopy (fNIRS) was used to collect cortical brain data for participants during each task, using 68 channels that covered the prefrontal cortex and the bilateral perisylvian regions. The interpreting-related neuroimaging data were normalized by using both L1 and L2 reading tasks, to control the function of reading and vocalization respectively. Our findings revealed the directionality effect in both groups, with forward interpreting (from L1 to L2) produced more pronounced brain activity, when normalized for reading. We also found that directionality was modulated by interpreting expertise in both normalizations. For the group with relatively high expertise, the activated brain regions included the right Broca’s area and the left premotor and supplementary motor cortex; whereas for the group with relatively low expertise, the activated brain areas covered the superior temporal gyrus, the dorsolateral prefrontal cortex, the Broca’s area, and visual area 3 in the right hemisphere. These findings indicated that interpreting expertise modulated brain activation, possibly because of more developed cognitive skills associated with executive functions in experienced interpreters.

中文翻译：

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基于方向性的大脑活动的光学映射及其通过普通话/英语口译专业知识的调制

最近的神经影像学研究表明，从语言 1 (L1) 到语言 2 (L2) 的口译与从 L2 到 L1 的口译之间存在不平等的认知努力。然而，形成这种方向性效应的神经基质尚不清楚。方向性是否受口译专业知识的调节也仍然未知。在这项研究中，我们招募了两组具有不同口译专业知识的普通话（L1）/英语（L2）双语人士，并要求他们执行口译和阅读任务。功能性近红外光谱 (fNIRS) 用于在每个任务期间为参与者收集皮质大脑数据，使用覆盖前额叶皮层和双侧侧裂区域的 68 个通道。通过使用 L1 和 L2 阅读任务对与口译相关的神经影像数据进行标准化，分别控制阅读和发声的功能。我们的研究结果揭示了两组的方向性效应，当阅读标准化时，正向解释（从 L1 到 L2）产生更明显的大脑活动。我们还发现方向性是通过解释两种标准化中的专业知识来调节的。对于专业知识相对较高的组，激活的大脑区域包括右侧布洛卡区和左侧前运动和辅助运动皮层；而对于专业知识相对较低的组，激活的大脑区域包括颞上回、背外侧前额叶皮层、布罗卡区和右半球的视觉区域 3。