Malik-Moraleda Saima, Cucu Theodor, Lipkin Benjamin, Fedorenko Evelina
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
Neurobiol Lang (Camb). 2021 Dec 23;2(4):647-664. doi: 10.1162/nol_a_00058. eCollection 2021.
The bilingual experience may place special cognitive demands on speakers and has been argued to lead to improvements in domain-general executive abilities, like cognitive control and working memory. Such improvements have been argued for based on both behavioral and brain imaging evidence. However, the empirical landscape is complex and ridden with controversy. Here we attempt to shed light on this question through an fMRI investigation of relatively large, relatively homogeneous, and carefully matched samples of early balanced bilinguals ( = 55) and monolinguals ( = 54), using robust, previously validated individual-level markers of neural activity in the domain-general multiple demand (MD) network, which supports executive functions. We find that the bilinguals, compared to the monolinguals, show significantly stronger neural responses to an executive (spatial working memory) task, and a larger difference between a harder and an easier condition of the task, across the MD network. These stronger neural responses are accompanied by better behavioral performance on the working memory task. We further show that the bilingual-vs.-monolingual difference in neural responses is not ubiquitous across the brain as no group difference in magnitude is observed in primary visual areas, which also respond to the task. Although the neural group difference in the MD network appears robust, it remains difficult to causally link it to bilingual experience specifically.
双语体验可能会对使用者提出特殊的认知要求，并且有人认为这会导致诸如认知控制和工作记忆等领域通用的执行能力得到提升。基于行为和脑成像证据，人们提出了这样的提升观点。然而，实证情况很复杂且充满争议。在此，我们试图通过功能磁共振成像（fMRI）研究来阐明这个问题，该研究针对相对较大、相对同质且经过仔细匹配的早期平衡双语者样本（n = 55）和单语者样本（n = 54），使用在支持执行功能的领域通用多重需求（MD）网络中经过先前验证的强大的个体水平神经活动标记。我们发现，与单语者相比，双语者在整个MD网络中对执行（空间工作记忆）任务表现出显著更强的神经反应，以及在任务的较难和较易条件之间存在更大差异。这些更强的神经反应伴随着在工作记忆任务上更好的行为表现。我们进一步表明，双语者与单语者在神经反应上的差异并非在全脑普遍存在，因为在同样对该任务有反应的初级视觉区域未观察到组间在反应强度上的差异。尽管MD网络中的神经组间差异看起来很显著，但仍难以将其具体地与双语体验建立因果联系。
