Sensorimotor adaptation-enduring changes to motor commands due to sensory feedback-allows speakers to match their articulations to intended speech acoustics. How the brain integrates auditory feedback to modify speech motor commands and what limits the degree of these modifications remain unknown. Here, we investigated the role of speech motor cortex in modifying stored speech motor plans. In a within-subjects design, participants underwent separate sessions of sham and anodal transcranial direct current stimulation (tDCS) over speech motor cortex while speaking and receiving altered auditory feedback of the first formant. Anodal tDCS increased the rate of sensorimotor adaptation for feedback perturbation. Computational modeling of our results using the Directions Into Velocities of Articulators (DIVA) framework of speech production suggested that tDCS primarily affected behavior by increasing the feedforward learning rate. This study demonstrates how focal noninvasive neurostimulation can enhance the integration of auditory feedback into speech motor plans.

中文翻译：

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左腹侧运动皮层的无创神经刺激增强了言语产生中的感觉运动适应

感觉运动适应——由于感觉反馈对运动命令的持久变化——允许说话者将他们的发音与预期的语音声学相匹配。大脑如何整合听觉反馈来修改语音运动命令以及限制这些修改的程度仍然未知。在这里，我们研究了语音运动皮层在修改存储的语音运动计划中的作用。在受试者内部设计中，参与者在说话和接收第一共振峰的改变的听觉反馈时，在语音运动皮层上接受了单独的假手术和阳极经颅直流电刺激 (tDCS)。阳极 tDCS 增加了对反馈扰动的感觉运动适应率。使用语音生成的方向进入咬合器速度 (DIVA) 框架对我们的结果进行计算建模表明，tDCS 主要通过增加前馈学习率来影响行为。这项研究展示了焦点无创神经刺激如何增强听觉反馈与言语运动计划的整合。