Imaging the Neural Effects of Transcranial Direct Current Stimulation

调查使用非侵入性电刺激(例如，经颅直流电)的研究 刺激(TDC))，为神经和精神障碍提供了令人信服的证据 刺激可以调节行为和认知，甚至促进局灶性脑损伤后功能的恢复 伤害，其影响通常超过刺激期。众所周知，这些效果是通过以下方式实现的 改变目标大脑区域的兴奋性，但我们对导致这种情况的机制的理解 变化是有限的，以及诸如电流强度、持续时间和电极蒙太奇等变量的影响 仍未得到解释。为了增加我们对tdcs的神经生物学和行为影响的了解， 并优化临床应用程序，我们建议进行更广泛的一系列研究，以 描述大脑和行为对tdcs的反应。在磁共振成像(MRI)过程中，tDCs将 由与MRI兼容的恒流刺激器提供。一种动态成像技术(动脉自旋 用于测量灌注的标记(ASL)将与静息状态功能磁共振(使用BOLD)相结合 对比成像)来关联响应tdcs的大脑活动的分布--两者都直接在 电极和遥远的大脑区域(使用ASL)--这些区域之间具有功能连接 (使用静息状态下的粗体fMRI)。我们的目标是(1)测量大脑的血流反应(代用品 对于神经元活动)，以增加电流强度和刺激持续时间以建立剂量反应 曲线，然后将这种反应与观察到的行为变化联系起来，(2)比较行为和神经 不同电极蒙太奇/几何形状的影响，以及(3)检查直接和远程网络效应 TDCS在两个模型系统(电机和语言)中使用功能连通性分析。创新之处 拟议的研究集中在：(A)使用最先进的功能成像技术，提供 功能脑反应的定量测量，以及(B)同时进行tdcs和功能成像 允许动态跟踪整个大脑的tdcs的影响，并检测其短期和中期- 对本地和网络连接地区的长期影响。这项新研究的预期结果包括 确定tdcs效应的神经和生理基础，更好地定义功能性脑效应。 对各种刺激参数的响应，并提高了对治疗方法如何特效的理解 针对范围广泛的脑部疾病。这项调查的结果将为未来的研究提供 建立了一种成像和量化对tdcs的神经反应的方法。我们的研究结果可以是 用于优化和量化大脑区域和神经网络的调制，这些调制涉及各种 使用一种非侵入性、安全和经济高效的方法，具有 有可能对大量患者产生积极影响。

Research investigating the use of noninvasive electrical stimulation (e.g., transcranial direct current stimulation (tDCS)), for neurologic and psychiatric disorders has provided compelling evidence that such stimulation can modulate behavior and cognition, and even facilitate recovery of function after focal brain injury, with effects typically outlasting the stimulation period. It is known that these effects are achieved by altering excitability in targeted brain regions, but our understanding of the mechanisms that lead to such changes is limited, and the influence of variables such as current strength, duration, and electrode montage remains unexplained. To increase our understanding of the neurobiological and behavioral effects of tDCS, and optimize procedures for clinical applications, we propose a more extensive series of studies to characterize brain and behavioral responses to tDCS. During magnetic resonance imaging (MRI), tDCS will be delivered by an MRI-compatible, constant-current stimulator. A dynamic imaging technique (arterial spin labeling (ASL)) used to measure perfusion will be coupled with resting state functional MRI (using BOLD contrast imaging) to relate the distribution of brain activity in response to tDCS -- both directly under the electrode and in remote brain regions (using ASL)-- with functional connectivity between those regions (using resting state BOLD fmri). Our aims are to (1) measure the brain's blood flow response (a surrogate for neuronal activity) to increases in current strength and duration of stimulation to establish dose-response curves, then relate that response to observed behavioral changes, (2) compare the behavioral and neural effects of different electrode montages/geometries, and (3) examine direct and remote network effects of tDCS in two model systems (motor and language) using functional connectivity analysis. The innovation of the proposed study centers on (a) the use of a state-of-the-art functional imaging technique that provides a quantitative measure of functional brain response, and (b) simultaneous tDCS and functional imaging that allows both dynamic tracking of tDCS' effects across the brain and detection of its short- and intermediate- term effects on local and network-connected regions. Expected Results of this novel research include the identification of the neural and physiological bases for tDCS' effect, better-defined functional brain effects in response to various stimulation parameters, and improved understanding of how therapies can be specifically targeted for a broad range of brain disorders. Outcomes from this investigation will provide future studies with an established method for imaging and quantifying neural responses to tDCS. Results of our studies can be used to optimize and quantify modulations of brain regions and neural networks implicated in various neurologic and psychiatric disorders using a non-invasive, safe, and cost-effective method that has the potential to positively affect a large number of patients.