Label-free Optical Recording of Neuroelectric Activities

项目摘要 了解相互连接的神经元网络如何接收、存储和处理信息需要 神经电信号的并行和高质量记录。细胞内记录技术，如补丁 钳夹是有创性的，仅限于记录1-2个细胞。而胞外多电极阵列可以记录多个 细胞，它们是预制的，因此只能探测固定的位置。电活动的光学检测 提供所需的空间灵活性。钙传感器，如GCaMP，时间响应慢，而不是 适用于记录快速放电起搏神经元，如多巴胺能神经元。压敏 荧光蛋白质和染料具有更快的时间响应，但它们的记录时间通常受到以下限制 光漂白。 在这个项目中，我们将演示一种光学记录的正交化方法。这种方法，电致变色 光学电势记录(ECRE)利用了一种独特的材料特性--光吸收 电致变色膜的大小取决于施加的电压。我们检测了电致变色薄膜的光学反射 来读出细胞的电活动。该方法是真正的无标记的，即没有任何需要 被掺入细胞并扰乱细胞生理，不受光漂白或光毒性的限制。 在初步工作中，我们已经建立了一个灵敏的光学装置，能够检测到反射率的变化 电致变色薄膜对低至10微伏的电势作出响应。事实上，我们已经使用了ECORE 目的：成功记录神经元、心肌细胞和脑组织中的单细胞动作电位。有了这个 项目中，我们计划通过开发一个扫描eCORE平台来显著扩展ecore的能力 用于神经电活动的亚细胞测量的并行检测和ECORE显微镜。我们会 用ECORE探测中脑区多巴胺能神经元的功能连接。成就 这项工作将产生一种新的电生理工具，可以被其他研究小组使用。

Project Summary Understanding how a network of interconnected neurons receives, stores and processes information requires parallel and high quality recording of neuroelectric signals. Intracellular recording techniques such as patch clamp are invasive and limited to recording 1-2 cells. While extracellular multielectrode arrays can record multiple cells, they are pre-fabricated and thus can only probe fixed locations. Optical detection of electric activities provides the needed spatial flexibility. Calcium sensors such as GcaMP have a slow time response and not suitable to record fast-spiking pacemaker neurons such as dopaminergic neurons. Voltage-sensitive fluorescence proteins and dyes have much faster time response, but their recording time is usually limited by photobleaching. In this project, we will demonstrate an orthogonal approach of optical recording. This method, Electrochromic Optical Recording of Electric potentials (ECORE) makes use of a unique material property – optical absorption of an electrochromic film depends on applied voltages. We detect the optical reflection of an electrochromic film to read out cellular electrical activities. The method is truly label-free, i.e. free of any molecular probes that need to be incorporated into cells and perturb cellular physiology, and not limited by photobleaching or photo-toxicity. In preliminary work, we have built a sensitive optical setup that is able to detect the reflectivity change of the electrochromic film in response to electrical potentials as small as 10 microvolts. Indeed, we have used ECORE to successfully record single-cell action potentials in neurons, cardiomyocytes, and brain tissues. With this project, we plan to dramatically expand ECORE capabilities by developing a scanning ECORE platform for parallel detection and an ECORE microscope for subcellular measurement of neuroelectric activities. We will use ECORE to probe the functional connectivity of dopaminergic neurons in midbrain area. Accomplishment of this work will result in a new class of electrophysiological tools that can be used by other research groups.