Decoding network activity states using sparse optical sampling

项目摘要 这项建议的重点是开发新的技术方法，以研究本地电路如何 大脑皮层区域功能正常。这个项目的中心目标是开发一种新的记录方法， 我们称之为随机孔径测光法，它可以结合随机孔径测光法对网络状态进行光学监测 反映单个神经元活动的荧光钙指示剂探针。与传统不同 光度学方法是使用灵敏的光监视整个显微镜视场 探测器，在我们提出的将显微镜输出分割成多个平行图像路径的方法中， 每一个都通过一个不同的掩模，只允许光通过小孔传输。通过 监控通过掩模的总光透射率，该方法产生光信号 稀疏地对标有荧光活性指示器的神经元区域进行采样。通过雇用 多个独立的图像路径-每个路径包含具有不同随机排列的蒙版 光圈-我们可以生成多个信号，每个信号反映正在进行的网络活动，但 只有微弱的关联。我们的初步实验和计算机模拟表明，信号 来自四个独立的掩码路径可能足以解码由 对齿状回的输入层施加不同的刺激。拟议的工作将使用计算机 模拟、全细胞膜片钳记录和光学方法来优化和细化这一点 方法。然后，我们将验证这种新的光学方法解码网络状态的能力 批量加载荧光钙成像同时检测神经元行为 细胞内录音。我们已经使用了基于细胞内记录的方法来分析网络 通过最近出版的一系列四本出版物介绍了这些国家的情况。与这些先前的研究一样，建议的 实验工作将使用标准的急性啮齿动物脑片进行。我们相信这一点 该方法在提供电路功能的非侵入性“全电路”视图方面是独一无二的，并且将被 在识别特定网络状态和网络状态转换的动态方面特别有用。 这种方法与标准的多电极阵列记录和双光子情况也是互补的 成像技术。虽然这些方法也可以在大范围的脑组织中取样，但 这两种技术(和传统的细胞外单位记录)的主要目标都是估计活动 在单个神经元中。相比之下，我们的方法故意牺牲空间分辨率来生成 网络状态特定的光信号，具有高信噪比。由于我们的方法使用 标准钙指示剂染料和单光子激发，它可以很容易地在体内应用一旦 通过拟议的脑片实验，对方法细节进行了细化和验证。

Project Summary This proposal is focused on developing new technological approaches to study how local circuits in cortical brain regions function. The central goal of this project is to develop a new recording method, we term “random aperture photometry”, that can monitor network state optically in combination with fluorescent Ca indicator probes that reflect activity in individual neurons. Unlike conventional photometry approaches where the entire microscope field-of-view is monitored using a sensitive light detector, in the method we propose to split the microscope output into multiple parallel image paths, each passing through a different mask that only allows light transmission through small apertures. By monitoring the total light transmission through the mask, this method generates an optical signal that sparsely samples the field of neurons labeled with fluorescent activity indicators. By employing multiple, independent image paths—each containing a mask with a different random arrangement of apertures—we can generate multiple signals that each reflect the ongoing network activity but are only weakly correlated. Our preliminary experiments and computer simulations suggest that signals from four independent masked pathways will likely be sufficient to decode network states evoked by different stimuli applied to the input layer of the dentate gyrus. The proposed work will use computer simulations, whole-cell patch clamp recording and optical methods to optimize and refine this method. We then will validate the ability of this new optical method to decode network states using bulk-loaded fluorescent Ca imaging while simultaneously assaying neuronal behavior using multiple intracellular recordings. We have used the intracellular recording-based method of assaying network states through a series of four recent publications. As with these previous studies, the proposed experimental work will be conducted using standard acute rodent brain slices. We believe this method is unique in providing non-invasive “whole-circuit” views of circuit function and will be especially useful in identifying specific network states and the dynamics of network state transitions. This method is also complementary with standard multi-electrode array recordings and 2-photon Ca imaging techniques. While these methods also can sample over a wide area of brain tissue, the primary goal of both techniques (and conventional extracellular unit recordings) is to estimate activity in individual neurons. By contrast, our method intentionally sacrifices spatial resolution to generate network state-specific optical signals with high signal-to-noise ratios. Since our method uses standard Ca indicator dyes and single photon excitation, it can easily be applied in vivo once the methodological details are refined and validated through the proposed brain slice experiments.