Rapid imaging in 3D with a 2-photon microscope using acousto-optical deflectors

大脑如何处理关于身体和周围世界的信息是当今科学中最令人兴奋和最具挑战性的问题之一。然而，可用于研究神经元网络（脑细胞）行为的方法相当有限。双光子激光扫描显微镜是一种重要的研究工具，因为它可以用来观察活体脑组织内部和测量神经活动。不幸的是，目前的系统太慢，无法捕捉到快速的信号事件，这些信号事件发生在千分之一秒的时间尺度上，当它们流经脑组织时。在这个项目中，我们将开发一种新的更快的方法来制作神经元的电影，使用一种叫做声光偏转器（AOD）的光学设备来扫描样本上的激光束，并像创建电视图像一样构建图像。该项目的重点是克服使用aod的技术问题，这些问题往往会降低图像的分辨率和激光束激发用于监测活动的荧光探针的效率。一旦我们确定了纠正这些技术问题的最佳方法，我们将进入研究中最令人兴奋的方面。这涉及到以一种不同的方式使用aod，聚焦激光束而不是扫描它。如果这项技术可行，它将允许快速对焦图像（即在百万分之几秒内）。这将是神经科学研究向前迈出的重要一步，因为它将允许在快速电信号流过三维脑组织时进行实时监测。从长远来看，我们的发现可能会通过提供新的工具来提高我们对健康和疾病中大脑功能的认识，从而对心理健康产生影响。

The question of how the brain processes information about the body and the surrounding world is one of the most exciting and challenging problems in science today. However, the methods available for studying how networks of neurons (brain cells) behave are rather limited. Two-photon laser-scanning microscopy is an important research tool because it can be used to look inside living brain tissue and measure the neural activity. Unfortunately, the present systems are too slow to capture the rapid signalling events, which occur on the timescale of one thousandth of a second, as they flow through brain tissue. In this project we will develop a new faster method for making movies of neurons using an optical device called an acousto-optical deflector (AOD) to scan a laser beam over the specimen and build up a picture like the way a TV picture is created. The project focuses on overcoming the technical problems of using AODs, which tend to reduce the resolution of the image and the efficiency with which the laser beam excites the fluorescent probes used to monitor activity. Once we have determined the best way to correct for these technical problems we will move onto perhaps the most exciting aspect of the study. This involves using AODs in a different way, to focus the laser beam rather than scan it. If this works it would allow very rapid focusing of the image (i.e. in a few millionths of a second). This would be a major step forward in neuroscience research, as it would allow rapid electrical signals to be monitored in real time as they flow through 3dimensional brain tissue. In the longer term, our findings could have implications for mental health by providing new tools that improve our knowledge of brain function in health and disease.