Hayek Dayana, Flöel Agnes, Antonenko Daria
Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology, NeuroCure Clinical Research Center, Berlin, Germany.
Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany.
Front Hum Neurosci. 2018 Dec 6;12:482. doi: 10.3389/fnhum.2018.00482. eCollection 2018.
Action comprehension that is related to language or gestural integration has been shown to engage the motor system in the brain, thus providing preliminary evidence for the gestural-verbal embodiment concept. Based on the involvement of the sensorimotor cortex (M1) in language processing, we aimed to further explore its role in the cognitive embodiment necessary for gestural-verbal integration. As such, we applied anodal (excitatory) and sham transcranial direct current stimulation (tDCS) over the left M1 (with reference electrode over the contralateral supraorbital region) during a gestural-verbal integration task where subjects had to make a decision about the semantic congruency of the gesture (prime) and the word (target). We used a cross-over within-subject design in young subjects. Attentional load and simple reaction time (RT) tasks served as control conditions, applied during stimulation (order of three tasks was counterbalanced). Our results showed that anodal (atDCS) compared to sham tDCS (stDCS) reduced RTs in the gestural-verbal integration task, specifically for incongruent pairs of gestures and verbal expressions, with no effect on control task performance. Our findings provide evidence for the involvement of the sensorimotor system in gestural-verbal integration performance. Further, our results suggest that functional modulation induced by sensorimotor tDCS may be specific to gestural-verbal integration. Future studies should now evaluate the modulatory effect of tDCS on semantic congruency by using tDCS over additional brain regions and include assessments of neural connectivity.
与语言或手势整合相关的动作理解已被证明会激活大脑中的运动系统，从而为手势 - 言语具身化概念提供了初步证据。基于感觉运动皮层（M1）参与语言处理的情况，我们旨在进一步探究其在手势 - 言语整合所需的认知具身化中的作用。因此，在一项手势 - 言语整合任务中，我们对左侧M1施加阳极（兴奋性）和伪经颅直流电刺激（tDCS）（参考电极置于对侧眶上区域），在此任务中，受试者必须对手势（启动刺激）和单词（目标刺激）的语义一致性做出判断。我们在年轻受试者中采用了受试者内交叉设计。注意力负荷和简单反应时间（RT）任务作为对照条件，在刺激期间进行（三项任务的顺序进行了平衡）。我们的结果表明，与伪tDCS（stDCS）相比，阳极tDCS（atDCS）在手势 - 言语整合任务中缩短了反应时间，特别是对于不一致的手势和言语表达对，而对对照任务的表现没有影响。我们的研究结果为感觉运动系统参与手势 - 言语整合表现提供了证据。此外，我们的结果表明，感觉运动tDCS诱导的功能调制可能对手势 - 言语整合具有特异性。现在，未来的研究应该通过在其他脑区使用tDCS来评估tDCS对语义一致性的调制作用，并包括对神经连接性的评估。
