Previous studies regarding developmental stuttering (DS) suggest that motor neural networks are strongly affected. Transcranial magnetic stimulation (TMS) was used to investigate neural activation of the primary motor cortex in DS during movement execution, and the influence of muscle representations involved in movements on "surrounding" ones. TMS was applied over the contralateral abductor digiti minimi (ADM) motor representation, at rest and during the movement of homologue first dorsal interosseous muscles (tonic contraction, phasic movements cued by acoustic signalling, and "self-paced" movements). Results highlighted a lower cortico-spinal excitability of ADM in the left hemisphere of stutterers, and an enhanced intracortical inhibition in their right motor cortex (in comparison to fluent speakers). Abnormal intracortical functioning was especially evident during phasic contractions cued by "external" acoustic signals. An exaggerated inhibition of muscles not directly involved in intended movements, in stuttering, may be useful to obtain more efficient motor control. This was stronger during contractions cued by "external" signals, highlighting mechanisms likely used by stutterers during fluency-evoking conditions.

中文翻译：

---

肌肉激活对发育性口吃中周围运动网络的影响：一项 TMS 研究

先前关于发育性口吃 (DS) 的研究表明运动神经网络受到强烈影响。经颅磁刺激 (TMS) 用于研究运动执行期间 DS 中初级运动皮层的神经激活，以及运动中涉及的肌肉表征对“周围”肌肉表征的影响。TMS 应用于对侧小指外展肌 (ADM) 运动表征、静止和同源第一背骨间肌运动期间（强直收缩、声信号提示的相位运动和“自定步调”运动）。结果表明，口吃者左半球的 ADM 皮质-脊髓兴奋性较低，右运动皮层的皮质内抑制增强（与流利的说话者相比）。在“外部”声信号提示的阶段性收缩期间，皮质内功能异常尤为明显。在口吃中，对不直接参与预期运动的肌肉的过度抑制可能有助于获得更有效的运动控制。这在“外部”信号提示的收缩期间更强，突出了口吃者在流畅诱发条件下可能使用的机制。