Optical gearbox for high speed neural recording

基因编码功能指标的快速发展使科学家能够可视化 神经元活动与光在活的大脑在高时空分辨率。用于体内 测量在哺乳动物的大脑，激光扫描双光子荧光显微镜 (TPM)通常用于对表达基因编码功能的神经元进行成像， 指标TPM的顺序点扫描提供了无噪声的干净测量 串扰，并产生优异的信噪比。然而，通常采用的系统 设计用于以~10 Hz速率进行单面记录。新兴的高速 谷氨酸传感器和电压指示器通常需要大得多的帧速率（例如400-1000 Hz）。此外，对于钙指示器的3D多区域记录（例如，20个子图像平面， 40 Hz），还需要接近1000 Hz的图像帧速率。 在这里，我们建议开发一种光学齿轮箱，作为一个附加单元，它可以转换为 用于高帧率记录的常用激光扫描双光子显微镜。的 光学齿轮箱的本质是保存成像的最大总体数据吞吐量 系统，并允许用户以成像视场（FOV）为代价获得扫描线速率。 对于基于振镜、谐振振镜或多边形扫描仪的激光扫描显微镜， 系统仅在全FOV扫描时实现最高数据吞吐量。缩放（缩小FOV） 导致成比例地减少的数据吞吐量。相比之下，使用光学变速箱， 不会损失数据吞吐量。基于光学齿轮箱，我们将开发 两个应用程序。一种是适合谷氨酸和电压的高帧率2D成像 传感器，另一个是在3D中为多个区域分配kHz帧速率， 多区域钙成像（例如，以数十Hz的速率对数十个3D区域进行成像）。的 这种附加转换器的开发将使现有的两个- 光子显微镜不需要专门的和昂贵的新激光源， 硬件与软件这一发展将广泛促进研究界采取 神经科学研究中高速功能指标的进步的优势。

The rapid advance of genetically encoded functional indicators allows the scientists to visualize neuronal activities with light in the living brain at high spatiotemporal resolutions. For in vivo measurement in the mammalian brain, laser scanning two-photon fluorescence microscopy (TPM) is commonly employed to image the neurons expressing genetically encoded functional indicators. The sequential point scanning of TPM offers clean measurement without noise crosstalk and yields excellent signal-to-noise ratio. However, the commonly employed systems are designed to accommodate single-plane recording at ~10 Hz rate. The emerging high-speed glutamate sensors and voltage indicators often require much greater frame rate (e.g. 400-1000 Hz). Moreover, for 3D multiregional recording of calcium indicators (e.g. 20 sub image planes at 40 Hz), image frame rate near 1000 Hz is also required. Here we propose to develop an optical gearbox, which as an add-on unit can convert commonly used laser scanning two-photon microscopes for high frame rate recording. The essence of optical gearbox is to conserve the maximum overall data throughput of an imaging system and allow the users to gain scanning line rates at the cost of imaging field-of-view (FOV). For laser scanning microscopes based on galvo, resonant galvo or polygon scanners, the system achieves the highest data throughput only at full FOV scanning. Zoom (reducing FOV) leads to proportionally reduced data throughput. In comparison, with optical gearbox, there will be no loss on data throughput. Based on the optical gearbox, we will develop the capability for two applications. One is the high frame rate 2D imaging suitable for glutamate and voltage sensors and the other is to distribute the kHz frame rate for multiple regions in 3D for multiregional calcium imaging (e.g. image tens of 3D regions at tens of Hz rate). The development of this add-on converter will enable high speed 3D imaging with the existing two- photon microscopes without the need to have specialized and expensive new laser sources, hardware and software. This development will broadly facilitate the research community to take advantages of the advance of high-speed functional indicators in neuroscience research.