Mechanisms of experience-induced brain plasticity in the adult speech system

说话是一种非常复杂的人类行为，人们对其神经结构的了解还只有一部分。尽管对神经语音系统的了解有了巨大的进步，但关于该系统的组织、它与言语表现的关系，以及更重要的是，它在成年后的演变，仍然存在一些问题。尽管结构和功能会随着年龄的增长而正常下降，但健康的成年人的大脑在获得新技能后，如学习一种新的语言或演奏一种新的乐器，在整个一生中仍保持着修改其结构和组织的非凡能力。这种现象被称为经验依赖型大脑可塑性。除了技能学习，另一种诱导大脑可塑性的方法是使用一种名为“重复经颅磁刺激”或rTMS的设备。RTMS将磁刺激传递到特定的大脑区域，并可以改变它们的功能，这可以改善行为。 这项研究计划的目的是通过研究年龄和不同类型的经历如何改变语言系统的解剖和功能来更好地了解成人语言系统的神经生物学。为了达到这一总体目标，我们将进行一连串的研究。第一组研究将集中于优化rTMS协议，通过在语音系统的不同区域诱导可塑性来提高语音产量。由于脑刺激技术还没有针对语音研究进行优化，我们将测试不同的方案来诱导语音系统的可塑性，并确定在年轻人和老年人中产生最显著变化的方案。 利用这些研究产生的知识，我们将进行一项纵向语音训练研究，包括学习产生和感知新的语音。将招募三组健康的成年人。其中一组将只接受语音训练。第二组将只接受rTMS。第三组将同时获得这两项服务。预计同时接受rTMS和语言训练的那组人将表现出最具可塑性的证据，通过磁共振成像(MRI)测量，在行为上(增强的语言能力)和大脑中。 行为和核磁共振测量将在训练开始时、4周后和8周后进行，使我们能够检查行为和大脑变化的时间进程。这项研究计划将促进对健康人脑中经验诱导的可塑性机制的现有知识。拟议中的计划还将对神经语音系统的理论和知识做出重大贡献。最后，作为该计划的一部分产生的知识将有助于大脑增强技术和认知刺激应用的开发，这些技术和应用正在缺乏足够的科学和理论支持的情况下在世界各地开发和申请专利。

Speaking is a remarkably complex human action whose neural architecture is still only partly understood. Despite tremendous progress in understanding the neural speech system, several questions remain regarding the organization of this system, its relationship to speech performance, and, importantly, its evolution over the adult lifespan. Despite a normal decline of structure and functions with age, the healthy adult brain retains a remarkable capacity to modify its structure and organization across the entire lifespan, following the acquisition of new skills, such as learning to speak a new language or to play a new instrument. This phenomenon is known as experience-dependent brain plasticity. In addition to skill learning, another method to induce brain plasticity is through the use of a device called “repetitive transcranial magnetic stimulation” or rTMS. rTMS delivers magnetic stimulation to specific brain areas and can modify their functioning, which can enhance behaviour. The objective of this research program is to better understand the neurobiology of the adult speech system by investigating how age and different kinds of experience can change the anatomy and functioning of the speech system. To achieve this general objective, a series of studies will be conducted. The first set of studies will focus on optimizing a rTMS protocol to enhance speech production by inducing plasticity in different regions of the speech system. Because brain stimulation technologies are not yet optimized for the study of speech, we will test different protocols for inducing plasticity in the speech system and identify the one that produces the most significant changes in younger and older adults. Using the knowledge generated in these studies, we will conduct a longitudinal speech training study consisting in learning to produce and perceive new speech sounds. Three groups of healthy adults will be recruited. One group will receive only the speech training. The second group will receive only rTMS. The third group will receive both. It is expected that the group receiving both rTMS and the speech training will show the most evidence of plasticity, behaviourally (enhanced speech performance) and in the brain, measured using magnetic resonance imaging (MRI). Behavioural and MRI measurements will be made at the beginning of the training, after 4 weeks and after 8 weeks, allowing us to examine the time course of behavioural and brain changes. This research program will advance current knowledge of experience-induced plasticity mechanisms in the healthy human brain. The proposed program will also contribute significantly to theories and knowledge about the neural speech system. Finally, the knowledge generated as part of the program will contribute to the development of brain-enhancing technologies and cognitive stimulation applications, which are being developed and patented across the world in the absence of adequate scientific and theoretical support.