Single cone contributions to color perception using adaptive optics

描述(申请人提供)：想象一种技术，能够非侵入性地识别活体人类视网膜中的单个视锥细胞，并选择性地刺激它们研究它们对视觉感知的贡献。这项技术还可以追踪视觉暗点边缘的视网膜功能组织，以研究治疗方案的机制、疾病和结果。这项技术目前还不存在，但当前一代自适应光学扫描激光检眼镜(AOSLO)凭借其独特的补偿视网膜运动和成像锥体马赛克的能力，非常接近。剩下的障碍是实时校正红外光和可见光激光之间的横向色差(TCA)，以便我们能够每天重复、连续和可靠地对单个识别的锥体进行成像和刺激。实现和验证这一能力是本提案的主要目标(目标1)。TCA误差校正的验证包括物理(图像处理)和创新的感知(色移)技术，以表征刺激单锥体中心的准确性和可靠性。该方法包括对L&M锥类的快速识别，这本身就是一个重大的进步。在目标2中，我们在中心凹附近绘制出一组按类别识别的视锥细胞后，我们将刺激阵列内不同的单个L视锥和M视锥，而观察者则判断闪光的强度、色调和饱和度。这一单锥体刺激的目标集中在表征一个锥体内感知的稳定性和同一类锥体之间的一致性。这一步将建立锥体激活的参数和由此产生的感知，并澄清它可能对未来研究施加的任何限制。在这一过程中，我们希望证实或否定关于单个被探测锥体周围不同锥体类别邻域的后果的假设。在目标3中，我们研究光适应的机制；它是否发生在单个锥体内？凭借我们卓越的图像稳定度，小而稳定、强烈的底座被送到锥体中心，预计会导致特罗克斯勒的快速褪色。一旦褪色，基座可能不会使增量测试响应饱和(就像在韦斯泰默效应中那样)，而是在很大程度上像一个均匀的场，具有恒定的锥体选择性韦伯定律行为。看起来像是视锥饱和的现象可能是眼震引起的。拟议的单锥体研究将证明AOSLO的能力。未来的研究将同时和独立地刺激多个已识别的视锥细胞，同样容易进行，并能够解决从颜色到空间视觉的研究问题。

DESCRIPTION (provided by applicant): Imagine a technology able to noninvasively identify individual cones in the living human retina and selectively stimulate them to study their contribution to visual perception. This technology could also track retinal functional organization at the border of a visual scotoma to study mechanisms disease and outcomes of treatment regimes. The technology does not yet exist but the current generation of the adaptive optics scanning laser ophthalmoscope (AOSLO), with its unique ability to compensate for retinal motion and image the cone mosaic, comes very close. The remaining obstacle is real time correction of transverse chromatic aberration (TCA) between the infrared beam and a visible light laser beam so that we can repeatedly, continuously and reliably image and stimulate the individual identified cones from day to day. Achieving and validating this capability is the principal goal (Aim 1) of this proposal. The validation of TCA error correction includes both physical (image processing) and innovative perceptual (chromatic shifts) techniques of characterizing the accuracy and reliability of stimulating the center of single cones. The method includes rapid identification of L & M cone classes which is itself a significant advance. In Aim 2, after we map out an array of cones identified by class near the fovea, we will stimulate different single L and M cones within the array while observers judge the intensity, hue and saturation of the flash. This single cone stimulation aim focuses on characterizing the stability of percepts within a cone and consistency across cones of the same class. This step will establish the parameters of cone activation and resultant percepts and clarify any constraints it might impose on future research. Along the way we expect to confirm or discredit hypotheses on the consequences of different cone class neighborhoods around the single probed cone. In Aim 3 we examine mechanisms of light adaptation; does it occur within a single cone? With our superior image stabilization, small steady, intense pedestals delivered to the center of a cone are expected to result in rapid Troxler fading. Once faded, the pedestal may not saturate the incremental test response (as in the Westheimer effect) but instead act largely like a uniform field with a constant cone-selective Weber law behavior. What appeared to be cone saturation may result from eye tremor. The proposed single cone studies will demonstrate the capabilities of the AOSLO. Future studies involving simultaneous and independent stimulation of multiple identified cones will be just as easy to perform and be able to address research questions extending from color to spatial vision in general.