Development of a novel in vivo imaging system and its application to place cells

本研究首先构建了表达绿色荧光蛋白（GFP）的慢病毒载体，并将其注射到小鼠海马CA1区，构建了一种新型的活体成像系统，可以在动物体内长期观察脑的高级功能。几周后，在荧光显微镜下在急性切片的区域中观察到强GFP信号。此外，慢病毒感染对GFP表达的神经元的电生理特性，包括长时程增强（LTP）表达没有影响。接下来，我们试图通过梯度折射率（GRIN）透镜观察类似切片的荧光图像，然而，图像是模糊的。梯度折射率透镜将脑内的图像传输到脑外，在活体成像系统中起着关键作用。因此，在未来，有必要通过提高信噪比来改进系统。

In the present work, we tried to develop a novel in vivo imaging system, which can be equipped with a freely moving animal for a long period, to understand higher brain functions.We first made green fluorescence protein (GFP)-expressing lentivirus vector, and then injected it to mouse hippocampus CA1 region. A few weeks later, strong GFP signals were observed in the region of the acute slice under a fluorescence microscope. In addition, the lentivirus infection had no influence on electrophysiological properties, including long-term potentiation (LTP) expression, of GFP-expressed neurons. Next, we tried to observed fluorescence images of the similar slice via gradient index (GRIN) lens, however, the images were faint. GRIN lens is thought to play a key role in in vivo imaging system because it transfer the images from the inside of the brain to the outside. In the future, therefore, it is necessary to improve the system by increasing signal-to-noise ratio.