Smalle Eleonore H M, Panouilleres Muriel, Szmalec Arnaud, Möttönen Riikka
Psychological Sciences Research Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
Institute of Neuroscience, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
Sci Rep. 2017 Oct 25;7(1):13966. doi: 10.1038/s41598-017-14547-x.
Adults do not learn languages as easily as children do. It has been hypothesized that the late-developing prefrontal cortex that supports executive functions competes with procedural learning mechanisms that are important for language learning. To address this hypothesis, we tested whether a temporary neural disruption of the left Dorsolateral Prefrontal Cortex (DLPFC) can improve implicit, procedural learning of word-forms in adults. Young adults were presented with repeating audio-visual sequences of syllables for immediate serial recall in a Hebb repetition learning task that simulates word-form learning. Inhibitory theta-burst Transcranial Magnetic Stimulation was applied to the left DLPFC or to the control site before the Hebb task. The DLPFC-disrupted group showed enhanced learning of the novel phonological sequences relative to the control group. Moreover, learning was negatively correlated with executive functions that rely on the DLPFC in the control group, but not in the DLPFC-disrupted group. The results support the hypothesis that a mature prefrontal cortex competes with implicit learning of word-forms. The findings provide new insight into the competition between brain mechanisms that contribute to language learning in the adult brain.
成年人学习语言不像儿童那样容易。据推测，支持执行功能的发育较晚的前额叶皮层与对语言学习很重要的程序学习机制相互竞争。为了验证这一假设，我们测试了左背外侧前额叶皮层（DLPFC）的暂时神经干扰是否能改善成年人对单词形式的隐性程序学习。在一项模拟单词形式学习的赫布重复学习任务中，向年轻人呈现重复的音节视听序列，以便进行即时序列回忆。在赫布任务之前，将抑制性θ波爆发经颅磁刺激应用于左DLPFC或对照部位。与对照组相比，DLPFC干扰组对新语音序列的学习增强。此外，在对照组中，学习与依赖DLPFC的执行功能呈负相关，但在DLPFC干扰组中并非如此。结果支持了成熟的前额叶皮层与单词形式的隐性学习相互竞争这一假设。这些发现为成年大脑中有助于语言学习的脑机制之间的竞争提供了新的见解。
