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Improvement of the optical recording system for detecting membrane potential from multiple site using CCD video camera by installing a liquid crystal panel in the light path.

通过在光路中安装液晶面板，改进了使用 CCD 摄像机检测多部位膜电位的光学记录系统。

基本信息

批准号：
12557003
负责人：
HIROTA Akihiko
金额：
$ 7.87万
依托单位：
Shimane University (School of Medicine)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

项目摘要

We have developed optical system for monitoring the membrane potential using CCD video camera. Since the size of membrane potential change is proportional to the fractional change (change in fluorescent light divided by the resting fluorescent light level) of the optical signal, it must be an ideal condition for optical recording using CCD video camera that the resting fluorescent light level is uniform. If there are not so many differences among the DC level in each CCD camera pixel, it is possible to subtract constant DC value from the output of CCD camera and then amplified for improvement the signal to noise level in optical signals. For this purpose, we have tried to install a liquid crystal panel in the light path and controlled the level of incident light in each pixel independently.In 2000 and 2001, we bought a high speed CCD camera and match its frame speed to 1000 frames per second, changed the camera controller and changed the do power supply to a stable one with very low ripple. In 2002, we bought a microtome with an oscillating blade, and tried to record the membrane potential optically from live slice preparation. Finally it was found that the saturation level of the CCD camera was too low to detect the membrane potential using absorption optical signals. In 2004, we tried in situ recording from the cerebrum of rat, but the moving artifact, which derived from the respiration and/or heartbeat, was very big. So, we cannot record the membrane potential dependent optical signal without summation of the optical signal. The saturation level of our CCD camera is sometimes not large enough for the brightest point even illuminated by a tungsten-halogen lamp. Installing a liquid crystal panel in the light path makes it possible to increase the intensity of the incident light and then the signal to noise level seems much improved, but the noise level is still not small enough for a single sweep optical recording.

我们研制了一套用CCD摄像机监测膜电位的光学系统。由于膜电位变化的大小与光信号的分数变化（荧光的变化除以静止荧光水平）成比例，因此静止荧光水平均匀一定是使用CCD摄像机进行光学记录的理想条件。如果在每个CCD摄像机像素中的DC电平之间没有太多的差异，则可以从CCD摄像机的输出中减去恒定的DC值，然后放大以改善光信号中的信噪比。为此，我们尝试在光路中安装液晶面板，并独立控制每个像素的入射光水平。在2000年和2001年，我们购买了一台高速CCD摄像机，并将其帧速度匹配为每秒1000帧，更换了摄像机控制器，并将DO电源更换为涟漪很低的稳定电源。在2002年，我们买了一个切片机与振荡刀片，并试图记录膜电位光学从活切片制备。最后，发现CCD相机的饱和度太低，无法使用吸收光信号检测膜电位。2004年，我们尝试了在大鼠大脑中进行原位记录，但由于呼吸和/或心跳引起的运动伪影非常大。因此，我们不能记录膜电位依赖的光信号而不对光信号求和。我们的CCD相机的饱和度有时不够大，即使用卤钨灯照明也不足以达到最亮的点。在光路中安装液晶面板使得可以增加入射光的强度，并且然后信噪比水平似乎得到很大改善，但是噪声水平对于单次扫描光学记录来说仍然不够小。