NeuroNex Innovation Award: Voltage to Light Transducers (VoLT) Collaborative

大脑活动成像的能力对于理解我们如何学习、思考、感知、计划运动和行为是至关重要的。它还可以帮助了解神经系统疾病如何影响大脑功能，为治愈或治疗铺平道路。一个主要的挑战是，大脑活动是快速的（毫秒时间尺度），并且在小于千分之一毫米的空间尺度上运作。现有的工具可以对大脑活动进行成像，但它们有重要的局限性，比如速度太慢，跟不上快速的大脑活动，空间分辨率差，无法记录许多脑细胞，或者只能在大脑的非常表面进行成像。该项目的研究人员正在开发新的传感器，用于在动物模型中成像大脑活动，从而为研究界提供更强大的工具来研究健康和疾病中的大脑。研究人员设计了“电压指示器”，这是一种蛋白质，当神经元活跃时就会发出闪光。先前的研究证明了这项技术的潜力，但开发更好的版本是费力且耗时的。在这里，一种快速改善电压指示器的新方法正在开发并传播给更广泛的神经科学家和其他生物学家。该技术使用户能够在更快的时间尺度上获得改进版本。该项目还为研究生提供多学科的培训机会。监测大脑深处特定神经元的电压动态对于揭示神经元回路的功能至关重要，但由于现有工具的性能有限，因此具有挑战性。研究人员通过开发遗传编码电压指示器（GEVIs）来解决这一技术需求，这是一种基于膜的荧光蛋白，其亮度由跨膜电压调节。这项新兴技术有望实现记录体内许多细胞或亚细胞位置的电活动的梦想，并具有细胞类型特异性。虽然gevi已经在体内进行了有限数量的实验，但为了在体内更广泛地使用这些探针，还需要进一步改进它们的性能。特别是，gevi将受益于灵敏度、亮度和光稳定性的提高。为了解决当前指示物的局限性，研究人员正在开发一种显微镜平台，该平台可以通过自动监测指示物变体对电压变化的荧光响应来快速筛选指示物变体。研究人员也正在构建几个指示变异体文库，重点关注那些对感应电场或控制荧光激发或发射很重要的残基。所得到的指标在所有关键性能指标中都有全面的特征，以促进下游应用程序的部署。这个NeuroNex创新奖是“大脑计划”和美国国家科学基金会“理解大脑”活动的一部分。

The ability to image brain activity is critical to understand how we learn, think, sense, plan movements, and behave. It can also help understand how neurological disorders impact brain function, paving the way for cures or treatments. A major challenge is that brain activity is rapid (millisecond-timescale) and operates at spatial scales down to less than 1/1000th of a millimeter. There are existing tools to image brain activity, but they have important limitations, such as being too slow to follow fast brain activity, having poor spatial resolution, being unable to record from many brain cells or only allowing imaging at the very surface of the brain. The investigators of this project are developing new sensors for imaging brain activity in animal models, thereby providing the research community with more powerful tools to study the brain in health and disease. The investigators engineer "voltage indicators," which are proteins who emit flashes of light when neurons are active. Previous studies demonstrated the potential for this technology, but developing better versions is laborious and time-intensive. Here, a new methodology for rapidly improving voltage indicators is being developed and disseminated to the broader community of neuroscientists and other biologists. The technology enables users to obtain improved versions on an accelerated timescale. The project also affords multi-disciplinary training opportunities for graduate students.Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits, but is challenging due to the limited performance of existing tools. The investigators address this technical need by developing Genetically Encoded Voltage Indicators (GEVIs), membrane-based fluorescent proteins whose brightness is modulated by transmembrane voltage. This emerging technology promises to fulfill the dream of recording electrical activity from many cells or subcellular locations in vivo and with cell type specificity. While GEVIs have enabled a restricted number of experiments in vivo, further improvement of their performance will be needed for broader use of these probes in vivo. In particular, GEVIs would benefit from increased sensitivity, brightness and photostability. To address the limitations of current indicators, the investigators are developing a microscopy platform that can rapidly screen indicator variants by automatically monitoring the variants' fluorescence responses to voltage changes. The investigators also are constructing several libraries of indicator variants, focusing on residues that are important for sensing the electrical field, or controlling fluorescence excitation or emission. The resulting indicators are characterized comprehensively across all key performance metrics to facilitate deployment in downstream applications. This NeuroNex Innovation Award is part of the BRAIN Initiative and NSF's Understanding the Brain activities.