Human Cone Transduction

人眼通过一层专门的 感光细胞和神经细胞称为视网膜，在 眼睛后面。 光能是用单位来描述的 也就是量子，将光能转化为神经信号 细胞的输出被称为转导。 电 光感受器内的反应是由最快的 已知的化学反应。 尽管这些反应速度很快， 这些单元的输出的总响应时间 慢到十分之一秒，因为 一系列生化反应，有效地放大 信号能量。 两种基本的光感受器， 视杆细胞和视锥细胞，在视网膜中启动视觉信号， 通过视神经传送到大脑。 圆锥系统是 通常用于在强日光照明下的色觉， 虽然杆系统对低光级非常敏感， 它本身并不携带颜色信息。 这个项目 探讨了视锥细胞转导的组成机制 在人眼中进行处理，使用人类的反应来获得 高度受控的刺激光阈值 持续时间和强度。 将对响应进行测量 当它处于一种 暗适应，在绝对吸收的量子数 不同球果类型和不同时间的阈值 暗适应锥反应中的成分。 这本小说 方法将产生重要的新的基本信息， 正常的人类视力，将进一步影响 了解视觉的生物化学和生理学， 将军

The human eye detects light by a sheet of specialized photoreceptor cells and nerve cells called the retina, at the back of the eye. Light energy is described in terms of units called quanta; the conversion of light energy to a neural signal output by the cell is called transduction. The electrical response within the photoreceptors is initiated by the fastest chemical reactions known. Despite the speed of these reactions, the total response time for the output of these cells is rather slow, to as much as a tenth of a second, because there is a cascade of biochemical reactions that effectively act to amplify the signal energy. Two basic kinds of photoreceptors, called rods and cones, initiate visual signals in the retina which then are sent to the brain by the optic nerve. The cone system is usually used for color vision in strong daylight illumination, while the rod system is very sensitive to low light level but does not carry color information by itself. This project examines the component mechanisms of the cone transduction process in the human eye, using human responses to obtain thresholds for seeing stimulus lights of highly controlled duration and intensity. Measurements will be made of responses to single flashes from the cone system when it is in a state of dark adaptation, of the number of quanta absorbed at the absolute threshold for different cone types, and of the different time components in the dark-adapted cone responses. This novel approach will generate important new fundamental information on normal human vision that will have impact on further understanding the biochemistry and physiology of vision in general.