Department of Psychology, York University, Toronto, Ontario, Canada.
Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
Neuropsychologia. 2018 Aug;117:352-363. doi: 10.1016/j.neuropsychologia.2018.06.023. Epub 2018 Jun 28.
Neuroimaging studies have reported overlapping neural circuits for cognitive control when engaging in tasks that involve verbal and nonverbal stimuli in young adult bilinguals. However, no study to date has examined the neural basis of verbal and nonverbal task switching in both monolinguals and bilinguals due to the inherent challenge of testing verbal task switching with monolinguals. Therefore, it is not clear whether the finding for overlapping networks is unique to bilingualism or indicative of general cognitive control. To address this question, the current study compared functional neural activation for young adults who were bilingual speakers of English and French or monolingual English speakers who had limited French learning experience ("functional monolinguals") on verbal and nonverbal task switching. Analyses showed common variance explaining general cognitive control in task switching across verbal and nonverbal domains for both groups, in line with the explanation that task switching involves general cognitive control, as well as unique brain regions recruited by monolinguals and bilinguals. Specifically, beyond the processing common to the tasks, monolinguals also recruited distinct networks for each of verbal and nonverbal switching but bilinguals used a common shared network. Thus, the domain-general aspect of switching is different for monolinguals and bilinguals.
神经影像学研究报告称，在年轻成年双语者参与涉及言语和非言语刺激的任务时，存在重叠的认知控制神经回路。然而，由于用单语者测试言语任务转换具有固有挑战，迄今为止，尚无研究检查单语者和双语者言语和非言语任务转换的神经基础。因此，对于重叠网络的发现是否仅适用于双语或是否表明一般认知控制，尚不清楚。为了解决这个问题，本研究比较了以英语和法语为双语的年轻成年人以及仅具有有限法语学习经验的英语单语者（“功能性单语者”）在言语和非言语任务转换中的功能神经激活。分析表明，两组在言语和非言语域中的任务转换中都存在解释一般认知控制的共同方差，这与任务转换涉及一般认知控制以及单语者和双语者所招募的独特大脑区域的解释一致。具体而言，除了任务共有的处理外，单语者还为言语和非言语转换各自招募了独特的网络，但双语者使用了共同的共享网络。因此，对于单语者和双语者来说，转换的领域一般性方面是不同的。
