Department of Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Division of Brain Circuits, National Institute for Basic Biology, Okazaki, Japan.
Elife. 2017 Sep 25;6:e26839. doi: 10.7554/eLife.26839.
In vivo two-photon calcium imaging currently allows us to observe the activity of multiple neurons up to ~900 µm below the cortical surface without cortical invasion. However, many important brain areas are located deeper than this. Here, we used an 1100 nm laser that underfilled the back aperture of the objective together with red genetically encoded calcium indicators to establish two-photon calcium imaging of the intact mouse brain and detect neural activity up to 1200 μm from the cortical surface. This imaging was obtained from the medial prefrontal cortex (the prelimbic area) and the hippocampal CA1 region. We found that neural activity before water delivery repeated at a constant interval was higher in the prelimbic area than in layer 2/3 of the secondary motor area. Reducing the invasiveness of imaging is an important strategy to reveal the intact brain processes active in cognition and memory.
在体双光子钙成像目前允许我们在不侵犯皮层的情况下观察皮层下约 900 µm 深度处的多个神经元的活动。然而，许多重要的脑区位于更深的位置。在这里，我们使用了一种 1100nm 的激光，该激光使物镜的后孔径未完全充满，同时使用红色遗传编码钙指示剂，建立了完整小鼠大脑的双光子钙成像，并从皮层表面检测到了 1200μm 深度的神经活动。这种成像来自于内侧前额叶皮层（前额叶区域）和海马 CA1 区域。我们发现，在水输送之前，重复出现的神经活动在前额叶区域比在次级运动区的第 2/3 层更高。降低成像的侵入性是揭示在认知和记忆中活跃的完整大脑过程的重要策略。
