Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64, Brno, Czech Republic.
Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745, Jena, Germany.
Nat Commun. 2023 Apr 5;14(1):1897. doi: 10.1038/s41467-023-36889-z.
Light-based in-vivo brain imaging relies on light transport over large distances of highly scattering tissues. Scattering gradually reduces imaging contrast and resolution, making it difficult to reach structures at greater depths even with the use of multiphoton techniques. To reach deeper, minimally invasive endo-microscopy techniques have been established. These most commonly exploit graded-index rod lenses and enable a variety of modalities in head-fixed and freely moving animals. A recently proposed alternative is the use of holographic control of light transport through multimode optical fibres promising much less traumatic application and superior imaging performance. We present a 110 μm thin laser-scanning endo-microscope based on this prospect, enabling in-vivo volumetric imaging throughout the whole depth of the mouse brain. The instrument is equipped with multi-wavelength detection and three-dimensional random access options, and it performs at lateral resolution below 1 μm. We showcase various modes of its application through the observations of fluorescently labelled neurones, their processes and blood vessels. Finally, we demonstrate how to exploit the instrument to monitor calcium signalling of neurones and to measure blood flow velocity in individual vessels at high speeds.
基于光的活体脑成像依赖于在高度散射组织中长距离的光传输。散射会逐渐降低成像对比度和分辨率，即使使用多光子技术，也很难到达更深的结构。为了达到更深的层次，已经建立了微创内窥显微镜技术。这些技术最常利用梯度折射率棒透镜，并在头部固定和自由移动的动物中实现各种模式。最近提出的替代方法是使用全息术来控制多模光纤中的光传输，这有望实现创伤更小的应用和更高的成像性能。我们提出了一种基于这一前景的 110μm 薄激光扫描内窥显微镜，能够在整个小鼠大脑深度进行体内体积成像。该仪器配备了多波长检测和三维随机访问选项，其横向分辨率低于 1μm。我们通过观察荧光标记的神经元、它们的过程和血管，展示了其各种应用模式。最后，我们演示了如何利用该仪器来监测神经元的钙信号，并以高速测量单个血管中的血流速度。
