THRESHOLD AND NOISE DETERMINATIONS IN RODS AND CONES

光感受器是视觉过程的第一个阶段，因此限制了动物从环境中提取的信息。光传导的增益、噪声和动力学，以及光感受器内段的膜特性，决定了哺乳动物视觉系统中视杆细胞和视锥细胞的最大性能。这反过来又设置了整体视觉系统性能的上限。该项目的长期目标是通过使用穿孔贴片技术研究猕猴视网膜中光感受器记录的光伏，量化人类视觉敏感性的生理机制。第一个目标是确定杆和锥体检测阈值作为背景强度的函数，并确定杆/锥体耦合的功能意义。光感受器阈值将直接与暗适应和光适应的心理物理阈值进行比较。第二个目标是确定杆状和锥状细胞中信号和噪声的时间频率特征，并与人类的时间灵敏度进行比较。第三个目标是确定小双极细胞对特定光谱类型的锥体的特异性，并确定锥体反应特性与突触后连接之间的关系。这些研究可以为形成人类ERG的光感受器成分的机制提供进一步的见解，并可能导致更深入地了解疾病对视网膜敏感性的影响。

Photoreceptors are the first stage in the visual process and therefore limit the information an animal can extract from its environment. The gain, noise and kinetics of phototransduction, along with the membrane properties of photoreceptor inner segments, determine the maximum performance of rods and cones in the mammalian visual system. This in turn sets the upper limit on overall visual system performance. The long-term goal of this project is to quantify the physiological mechanisms that underlie human visual sensitivity by studying the photovoltages recorded from photoreceptors in the macaque retina using a perforated patch technique. The first aim is to determine rod and cone detection thresholds as a function of background intensity and to determine the functional significance of rod/cone coupling. Photoreceptor thresholds will be directly compared to dark- adapted and light-adapted psychophysical thresholds. The second aim is to determine the temporal frequency characteristics of signal and noise in rods and cones and compare to human temporal sensitivity. The third aim is to determine the specificity of midget bipolar cells for cones of a particular spectral type and to determine the relationship between cone response properties and post-synaptic wiring. These investigations can provide further insights into the mechanisms that shape the photoreceptor component of the human ERG and can potentially lead to a greater understanding of the effects of disease on retinal sensitivity.