Compressive Light Field microscopy for optogenetic neural activity tracking

用于光遗传学神经活动跟踪的压缩光场显微镜

• 批准号: 9244514
• 负责人: Laura Waller
• 金额: $ 22.47万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-30 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9244514
• 关键词: Algorithms; Animal Model; Animals; Area; BRAIN initiative; Back; Behavior; Brain; Brain imaging; Cerebrum; Cognition; Communities; Data; Data Analyses; Devices; Electrodes; Four-dimensional; Functional Imaging; Goals; Head; Image; Imaging Techniques; Imaging technology; Individual; Life; Light; Machine Learning; Maps; Measurement; Measures; Mediating; Methodology; Methods; Microscope; Microscopy; Modeling; Mus; Neurons; Neurosciences; Pathway interactions; Perception; Phase; Photons; Population; Positioning Attribute; Process; Records Controls; Resolution; Sampling; Scheme; Sensory; Side; Signal Transduction; Specimen; Speed; System; Techniques; Technology; Testing; Time; Tissues; Work; awake; brain tissue; brain volume; cost; density; design; detector; image reconstruction; imaging modality; imaging system; in vivo; light emission; light scattering; neural patterning; neurophysiology; novel; novel strategies; operation; optical imaging; optogenetics; reconstruction; relating to nervous system; research study; scale up; sensor; temporal measurement; tool; two-photon

SUMMARY: Understanding the mechanisms by which the living brain derives perception, cognition and behavior requires the ability to record and control electrical activity in many neurons simultaneously. Completely reconstructing the pattern of neural activity that mediates a specific neural operation is critical for fully understanding its underlying mechanism. This requires an approach that can measure neural activity on a large scale with high spatial and temporal resolution. Functional imaging of genetically encoded activity sensors is one of the most promising avenues towards achieving this goal because it permits dense sampling and unambiguous separation of nearby neurons1, 2. However, even techniques currently available cannot capture neural activity in large volumes of the brain simultaneously, at high speed, and with cellular resolution. Furthermore, these existing approaches rely on expensive and sophisticated hardware, and cannot be readily adapted for imaging in unrestrained animals. Since a central goal of the BRAIN initiative is to achieve large-scale recording of neural activity in behaving animals, a new imaging approach is needed to overcome these technical challenges. To achieve high speed, volumetric imaging in a compact and inexpensive device, we propose to develop a new imaging modality - compressive four-dimensional (4D) light field microscopy (LFM). In this approach, we will combine the advantages of light field microscopy with compressed sensing to extract the activity of thousands of individual neurons with high spatial and temporal resolution, through scattering tissue. In conventional microscopy, the photo-detector only samples the intensity of photons. In LFM, the sensor also captures the angle of the light. This allows 3D reconstruction, since position and angle enable back-tracing of rays of light. Such a scheme can be achieved simply by placing a lenslet array in the imaging pathway (Fig. 1A). The resulting 4D light field gives complete volumetric data at each time frame3-6. 3D activity can thus be sampled at camera-limited frame rates, much faster than conventional methods such as multiphoton or light sheet microscopy. For these reasons, LFM for functional brain imaging could revolutionize experimental neuroscience. Unfortunately, imaging methods which operate in the one-photon regime suffer from light scattering. To image activity in the mammalian brain, we must consider the effects of tissue scattering through the 3D volume. We propose to apply a new approach to processing light field data for better reconstructions of neurons through scattering media37,38. Since the effect of scattering is to spread the angles of propagation of light, measuring angle information inherently helps to characterize and mitigate scatter effects. Our method leverages compressed sensing algorithms, which exploit the sparsity of the light emission in 3D space and time. Importantly, the volume and resolution limits of our method are not set by the number of pixels captured, but rather by the number of active neurons at any given time. Thus, we will be able to localize and measure the activity of thousands or millions of individually active neurons in large volumes of cerebral cortical tissue.

摘要：了解活的大脑产生感知，认知和行为的机制 需要同时记录和控制许多神经元的电活动。完全 重建介导特定神经操作的神经活动模式对于充分理解神经元的功能至关重要。 了解其潜在机制。这需要一种方法，可以测量神经活动的大规模 具有较高的空间和时间分辨率。基因编码活动传感器的功能成像是一种 实现这一目标的最有希望的途径，因为它允许密集的采样和明确的 分离附近的神经元1，2.然而，即使是目前可用的技术也不能捕捉到大脑中的神经活动。 大体积的大脑同时，在高速，并与细胞的分辨率。此外，这些现有 方法依赖于昂贵和复杂的硬件，并且不能容易地适用于成像， 无拘无束的动物由于BRAIN计划的一个中心目标是实现大规模的神经记录， 为了研究动物行为的活动，需要一种新的成像方法来克服这些技术挑战。 为了实现高速，体积成像在一个紧凑和廉价的设备，我们建议开发 一种新的成像模式-压缩四维（4D）光场显微镜（LFM）。在这种方法中，我们 将结合联合收割机的优势，光场显微镜与压缩传感提取的活动， 成千上万的个体神经元，具有高的空间和时间分辨率，通过散射组织。在 在传统的显微镜中，光检测器仅对光子的强度进行采样。在LFM中，传感器还 捕捉光线的角度。这允许3D重建，因为位置和角度使得能够回溯 光线。这种方案可以简单地通过在成像路径中放置小透镜阵列来实现（图1A）。 由此产生的4D光场提供了每个时间帧的完整体积数据3 -6。因此，可以对3D活动进行采样 在相机限制的帧速率下，比多光子或光片等传统方法快得多 显微镜由于这些原因，用于功能性脑成像的LFM可能会彻底改变实验神经科学。 不幸的是，在单光子机制中操作的成像方法遭受光散射。到 在哺乳动物大脑中的图像活动，我们必须考虑通过3D体积的组织散射的影响。 我们提出了一种新的方法来处理光场数据，以更好地重建神经元， 散射介质37，38.由于散射的效果是扩展光的传播角度，因此测量 角度信息固有地有助于表征和减轻散射效应。我们的方法 压缩感测算法，其利用3D空间和时间中的光发射的稀疏性。 重要的是，我们的方法的体积和分辨率限制不是由捕获的像素数来设置的，而是 而是由在任何给定时间活跃神经元的数量决定。因此，我们将能够定位和测量 在大量的大脑皮层组织中，数千或数百万个单独活跃的神经元的活动。