Mapping the Human Brain Circuitry and Function through Transcranial Magnetic Stimulation Combined with Electroencephalography

最近在绘制人类大脑结构和功能方面的全球倡议激发了科学界设计创新技术以安全可靠地确定大脑结构和功能健康指标的热情。在过去的六年里，我们为推进一种科学方法做出了贡献，该方法涉及同时结合非侵入性脑刺激技术（称为经颅磁刺激（TMS））和非侵入性神经记录方法（称为脑电图（EEG））。这项技术已经能够将对人类大脑回路的研究从大脑切片或动物模型转移到对人类完整头皮的大脑回路的研究。这种结合允许以输入-输出（TMS-EEG）的方式检查大脑回路。当颅磁刺激脉冲被传送到大脑的某个区域时，它可以激活神经元。经颅磁刺激的参数可以被选择来激活一个特定的电路，例如抑制，大脑制动机制。然后，脑电图捕捉到激活电路的反应。分析脑电图记录以提取与该特定电路完整性相关的指标。通过比较不同大脑区域、个体或时间的这些指标，TMS-EEG可以让我们检查和监测特定的大脑过程。然而，TMS-EEG作为脑健康解码和监测工具的广泛应用，进一步依赖于该技术的验证和标准化。研究表明，大脑回路会随着年龄和行为状态（如休息和执行任务）而变化。此外，脑电信号是多维的，可以使用多种算法对其进行表征。我们的研究项目旨在应对这些挑战和机遇。在接下来的五年里，我们将致力于在年轻、中年和老年健康受试者中确定两个关键的大脑过程的可靠指标，这些大脑过程涉及多个大脑区域和行为状态的抑制和连接。同时，我们通过开发和改进脑电信号处理算法，并将TMS-EEG与其他神经成像方法进行比较，进一步完善了TMS-EEG工具。我们的研究项目将为TMS-EEG作为一种脑成像技术的有效性和附加价值提供重要的见解。我们的项目将为神经抑制的特征和不同大脑状态的连接提供重要的见解，使我们离最终获得人类大脑电特性和健康指标的图谱更近了一步。最后，我们的项目将为TMS-EEG在基础和认知神经科学、神经康复等各个学科的转化价值和应用提供关键证据，并指导设计廉价的解决方案来监测任何个体的整个生命周期的大脑健康。

The recent global initiatives in mapping the human brain structure and function have created enthusiasm in the scientific community to design innovative technologies to safely and reliably identify metrics of the brain structural and functional health. In the past six years, we have contributed to advancing a scientific approach that involves simultaneous combination of a non-invasive brain stimulation technique called transcranial magnetic stimulation (TMS) with a non-invasive neural recording method called electroencephalography (EEG). This technique has enabled transferring the investigation of the human brain circuitries from brain slices or animal models to investigation of the brain circuitry from the intact scalp of humans. This combination permits examining the brain circuitries in an input-output (TMS-EEG) manner. When a TMS pulse is delivered to a brain region, it can activate neurons. The parameters of TMS can be chosen to activate a specific circuitry, for example inhibition, the brain braking mechanism. Then, EEG captures the response of this activated circuitry. EEG recordings are analyzed to extract metrics related to integrity of this specific circuitry. By comparing these metrics across different brain regions, individuals or over time, TMS-EEG can allow us to examine and monitor specific brain processes. However, the wide spread application of TMS-EEG as a tool for decoding and monitoring the brain health further relies on validation and standardization of this technique. It has been shown that the brain circuitries change across age and behavioral states such as resting compared to performing a task. Furthermore, EEG signals are multidimensional and several algorithms can be employed to characterize them. Our research program is designed to address these challenges and opportunities. In the next five years, we will contribute to identifying reliable metrics of two key brain processes of inhibition and connectivity across several brain regions and behavioral states in young, middle age and old healthy subjects. In parallel, we advance TMS-EEG tool by developing and refining EEG signal processing algorithms and comparing TMS-EEG with other neuroimaging methods. Our research program will provide important insight into the validity and added value of TMS-EEG as a brain mapping technology. Our program will provide important insight into characteristics of neural inhibition and connectivity across different brain states, taking us a step closer to ultimately obtaining an atlas of the human brain electrical properties and metrics of health. Finally, our program will provide critical evidence in support of the translational value and application of TMS-EEG in various disciplines of basic and cognitive neuroscience, neurorehabilitation, and in guiding the design of inexpensive solutions for monitoring the brain health across the life span in any individual.