Kemmerer David
Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IND, United States.
Department of Psychological Sciences, Purdue University, West Lafayette, IND, United States.
Front Hum Neurosci. 2022 Sep 23;16:923022. doi: 10.3389/fnhum.2022.923022. eCollection 2022.
Among the many lines of research that have been exploring how embodiment contributes to cognition, one focuses on how the neural substrates of language may be shared, or at least closely coupled, with those of action. This paper revisits a particular proposal that has received considerable attention-namely, that the forms of hierarchical sequencing that characterize both linguistic syntax and goal-directed action are underpinned partly by common mechanisms in left Brodmann area (BA) 44, a cortical region that is not only classically regarded as part of Broca's area, but is also a core component of the human Mirror Neuron System. First, a recent multi-participant, multi-round debate about this proposal is summarized together with some other relevant findings. This review reveals that while the proposal is supported by a variety of theoretical arguments and empirical results, it still faces several challenges. Next, a narrower application of the proposal is discussed, specifically involving the basic word order of subject (S), object (O), and verb (V) in simple transitive clauses. Most languages are either SOV or SVO, and, building on prior work, it is argued that these strong syntactic tendencies derive from how left BA44 represents the sequential-hierarchical structure of goal-directed actions. Finally, with the aim of clarifying what it might mean for syntax and action to have "common" neural mechanisms in left BA44, two different versions of the main proposal are distinguished. Hypothesis 1 states that the very same neural mechanisms in left BA44 subserve some aspects of hierarchical sequencing for syntax and action, whereas Hypothesis 2 states that anatomically distinct but functionally parallel neural mechanisms in left BA44 subserve some aspects of hierarchical sequencing for syntax and action. Although these two hypotheses make different predictions, at this point neither one has significantly more explanatory power than the other, and further research is needed to elaborate and test them.
在众多探索具身性如何促进认知的研究方向中，有一个方向聚焦于语言的神经基础如何与动作的神经基础共享，或者至少紧密耦合。本文重新审视了一个备受关注的特定提议，即表征语言句法和目标导向动作的层次序列形式部分由左侧布罗德曼区（BA）44的共同机制支撑，该皮质区域不仅传统上被视为布洛卡区的一部分，也是人类镜像神经元系统的核心组成部分。首先，总结了最近关于该提议的多参与者、多轮辩论以及其他一些相关发现。这一综述表明，虽然该提议得到了各种理论论证和实证结果的支持，但它仍然面临一些挑战。接下来，讨论了该提议的一个更狭义的应用，具体涉及简单及物从句中主语（S）、宾语（O）和动词（V）的基本词序。大多数语言要么是主宾谓（SOV）型，要么是主谓宾（SVO）型，基于先前的研究，有人认为这些强烈的句法倾向源于左侧BA44对目标导向动作的序列层次结构的表征方式。最后，为了阐明在左侧BA44中句法和动作拥有“共同”神经机制可能意味着什么，区分了主要提议的两个不同版本。假设1指出，左侧BA44中完全相同的神经机制服务于句法和动作的层次序列的某些方面，而假设2指出，左侧BA44中在解剖学上不同但功能平行的神经机制服务于句法和动作的层次序列的某些方面。尽管这两个假设做出了不同的预测，但目前两者都没有比对方具有显著更强的解释力，需要进一步的研究来详细阐述和检验它们。
