School of Psychology, Bangor University, Bangor, LL57 2AS, UK.
Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, 19716, USA.
Cerebellum. 2019 Feb;18(1):47-55. doi: 10.1007/s12311-018-0949-y.
A consensus has emerged that the cerebellum makes important contributions to a spectrum of linguistic processes, but that the psychobiology of these contributions remains enigmatic (Mariën et al., Cerebellum 13(3):386-410, 2014). One aspect of this enigma arises from the fact that, although the language-dominant left cerebral hemisphere is connected to the right cerebellum, distinctive contributions of the left cerebellar hemisphere have been documented (Murdoch and Whelan, Folia Phoniatr Logop 59:184-9, 2007), but remain poorly understood. Here, we report that neurodisruption of the left and right cerebellar hemispheres have opposite effects on associative word priming in a lexical decision task. Reaction time was measured for decisions on whether a target letter string constituted a word (e.g. bread) or, with equal probability, a pronounceable non-word (e.g. dreab). A prime word was presented for 150 ms before the target and could either, and with equal probability, be related (e.g. BUTTER) or unrelated (TRACTOR). Associative word priming was computed as the reduction in lexical decision RT on trials with related primes. Left cerebellar hemisphere continuous theta-burst transcranial magnetic stimulation (TMS) decreased, and right hemisphere stimulation increased, priming. The results suggest that the cerebellum contributes to predictive sequential processing, in this case language, through an opponent process mechanism coordinated by both cerebellar hemispheres.
目前已经达成共识，即小脑对一系列语言过程做出了重要贡献，但这些贡献的心理生物学机制仍然扑朔迷离（Mariën 等人，《小脑》13(3):386-410, 2014）。这种神秘感的一个方面源于一个事实，即尽管语言优势的左大脑半球与右小脑相连，但已经记录到左小脑半球的独特贡献（Murdoch 和 Whelan，《语音学与言语治疗学杂志》59:184-9, 2007），但仍知之甚少。在这里，我们报告称，对左、右小脑半球的神经破坏对词汇判断任务中的联想词启动有相反的影响。我们测量了对目标字母串是否构成单词（例如 bread）或具有同等可能性的可发音非单词（例如 dreab）的决策的反应时间。在目标出现之前，呈现 150 毫秒的启动词，并且可以是相关的（例如 BUTTER）或不相关的（例如 TRACTOR）。联想词启动是通过相关启动词试验中词汇判断 RT 的减少来计算的。左小脑半球连续 theta 爆发经颅磁刺激（TMS）减少了启动作用，而右半球刺激则增加了启动作用。结果表明，小脑通过由两个半球协调的对立过程机制，有助于预测性序列处理，在这种情况下是语言。
