Nuttall Helen E, Kennedy-Higgins Dan, Devlin Joseph T, Adank Patti
Department of Psychology, Fylde College, Lancaster University, Lancaster LA1 4YF, UK; Department of Speech, Hearing and Phonetic Sciences, University College London, Chandler House, 2 Wakefield Street, London WC1N 1PF, UK.
Department of Speech, Hearing and Phonetic Sciences, University College London, Chandler House, 2 Wakefield Street, London WC1N 1PF, UK.
Brain Lang. 2018 Dec;187:74-82. doi: 10.1016/j.bandl.2017.12.002. Epub 2018 Feb 4.
Primary motor (M1) areas for speech production activate during speechperception. It has been suggested that such activation may be dependent upon modulatory inputs from premotor cortex (PMv). If and how PMv differentially modulates M1 activity during perception of speech that is easy or challenging to understand, however, is unclear. This study aimed to test the link between PMv and M1 during challenging speech perception in two experiments. The first experiment investigated intra-hemispheric connectivity between left hemisphere PMv and left M1 lip area during comprehension of speech under clear and distorted listening conditions. Continuous theta burst stimulation (cTBS) was applied to left PMv in eighteen participants (aged 18-35). Post-cTBS, participants performed a sentence verification task on distorted (imprecisely articulated), and clear speech, whilst also undergoing stimulation of the lip representation in the left M1 to elicit motor evoked potentials (MEPs). In a second, separate experiment, we investigated the role of inter-hemispheric connectivity between right hemisphere PMv and left hemisphere M1 lip area. Dual-coil transcranial magnetic stimulation was applied to right PMv and left M1 lip in fifteen participants (aged 18-35). Results indicated that disruption of PMv during speech perception affects comprehension of distorted speech specifically. Furthermore, our data suggest that listening to distorted speech modulates the balance of intra- and inter-hemispheric interactions, with a larger sensorimotor network implicated during comprehension of distorted speech than when speech perception is optimal. The present results further understanding of PMv-M1 interactions during auditory-motor integration.
用于言语产生的初级运动区（M1）在言语感知过程中会被激活。有人提出，这种激活可能依赖于来自运动前区皮质（PMv）的调节性输入。然而，在理解容易或具有挑战性的言语过程中，PMv如何以及是否会差异调节M1的活动尚不清楚。本研究旨在通过两个实验来测试在具有挑战性的言语感知过程中PMv与M1之间的联系。第一个实验研究了在清晰和失真的听力条件下理解言语时，左半球PMv与左M1唇部区域之间的半球内连接。对18名参与者（年龄在18 - 35岁之间）的左PMv施加连续theta爆发刺激（cTBS）。cTBS后，参与者对失真（发音不精确）和清晰的言语执行句子验证任务，同时还对左M1中的唇部表征进行刺激以诱发运动诱发电位（MEP）。在第二个单独的实验中，我们研究了右半球PMv与左半球M1唇部区域之间的半球间连接的作用。对15名参与者（年龄在18 - 35岁之间）的右PMv和左M1唇部施加双线圈经颅磁刺激。结果表明，言语感知过程中PMv的破坏特别影响对失真言语的理解。此外，我们的数据表明，听失真言语会调节半球内和半球间相互作用的平衡，与言语感知最佳时相比，在理解失真言语时涉及的感觉运动网络更大。目前的结果进一步加深了我们对听觉 - 运动整合过程中PMv - M1相互作用的理解。
