Liu Jessie R, Zhao Lingyun, Hullett Patrick W, Chang Edward F
Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA.
Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
Nat Hum Behav. 2025 Jul 16. doi: 10.1038/s41562-025-02250-1.
Fluent speech production is mediated by serially ordering and preparing motor plans corresponding to target speech sounds, a process known as speech-motor sequencing. Here we used high-density direct cortical recordings while 14 participants spoke utterances with varying phonemic and syllabic sequence complexity after reading a target sequence and a delay period. Phasic activations corresponding to speech production and auditory feedback were observed, but also sustained neural activity that persisted throughout all task phases including the target presentation, the delay period and production of the sequence. Furthermore, sustained activity in a specific area, the middle precentral gyrus (mPrCG), was both modulated by sequence complexity and predicted reaction time, suggesting a role in speech-motor sequencing. Electrocortical stimulation of the mPrCG caused speech disfluencies resembling those seen in apraxia of speech. These results suggest that speech-motor sequencing is mediated by a distributed cortical network in which the mPrCG plays a central role.
流畅的言语产生是通过对与目标语音相对应的运动计划进行串行排序和准备来介导的，这一过程称为言语运动序列。在这里，我们使用高密度直接皮层记录，让14名参与者在阅读目标序列并经过延迟期后说出具有不同音素和音节序列复杂性的话语。观察到与言语产生和听觉反馈相对应的相位激活，同时也观察到在包括目标呈现、延迟期和序列产生在内的所有任务阶段持续存在的神经活动。此外，特定区域中央前回中部（mPrCG）的持续活动既受序列复杂性的调节，又能预测反应时间，表明其在言语运动序列中发挥作用。对mPrCG进行皮层电刺激会导致言语不流畅，类似于在言语失用症中看到的情况。这些结果表明，言语运动序列是由一个分布式皮层网络介导的，其中mPrCG起着核心作用。
