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

在目前的工作中，我们试图开发一种新的体内成像系统，该系统可以长时间配备在自由运动的动物身上，以了解更高的大脑功能。我们先制作表达绿色荧光蛋白（GFP）的慢病毒载体，然后将其注射到小鼠海马CA1区。几周后，在荧光显微镜下，在急性切片区域观察到强烈的GFP信号。此外，慢病毒感染对gfp表达神经元的电生理特性，包括长期增强（LTP）表达没有影响。接下来，我们尝试通过梯度折射率（GRIN）透镜观察相似切片的荧光图像，但图像模糊。GRIN透镜被认为在体内成像系统中起着关键作用，因为它将图像从大脑内部传输到外部。因此，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.