RECEPTOR-RELATED NONLINEARITIES IN PHOTOPIC VISION

明视觉中与受体相关的非线性

• 批准号: 3265969
• 负责人: MARCIA A FINKELSTEIN
• 金额: $ 5.99万
• 依托单位: UNIVERSITY OF SOUTH FLORIDA
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-09-30 至 1994-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3265969
• 关键词: biological models; color visions; cone cell; fovea centralis retinae; light adaptations; model design /development; psychophysics; visual fields; visual pathways; visual photoreceptor; visual photosensitivity; visual threshold

(Adapted from the applicant's abstract) The aim of the present study is to quantify and empirically evaluate a model of photopic detection and light adaptation. The experiments combine two approaches to the study of photopic sensitivity: the "adaptation" and the "color vision" approaches. The former examines foveal detection and adaptation with the probe-flash paradigm. Increment thresholds are measured for a brief target (the "probe") presented upon a flashed field (the "flash) to which the visual system has not had time to adapt. The probe flash techniques reveals nonlinearities in the cone system that are not evident with steady fields. In the color vision approach, models originally formulated to explain color appearance are applied to sensitivity data. The models assume that the detectability of a light depends on the activity it elicits in three pathways or channels. These include two opponent chromatic channels (red/green and yellow/blue) and one nonopponent achromatic pathway. Probe-flash data have been fit with models containing a single static nonlinearity. While the data are easily described by such models, the site of sensitivity loss within the visual pathway remains unclear. Psychophysicists initially assumed the data reflected nonlinearities within the cone receptors. However, a variety of measures reveal that under many conditions, desensitization occurs beyond the receptors, and involves spectrally opponent mechanisms. A two-site model was developed to account for the evidence of post- receptor nonlinearities in probe-flash data. One aim of current proposal is to formulate a model that predicts the effects of changes in adapting intensity. A secondary goal is to compare the static nonlinearities inferred psychophysically to primate physiology. Recent recordings of primate cone response functions provide a new opportunity for direct comparison between receptor physiology and behavior. Sensitivity in both long- and short-wavelength cone pathways will be examined. The latter provides a valuable subject of study because of its relative vulnerability to retinal disease. Probe-flash data obtained for these patients have generated some disagreement as to whether the observed falloff in sensitivity reflects receptor or post-receptor deficits. By isolating receptor and opponent nonlinearities in normal observers, and comparing the results to primate receptor data, some insights into the locus of sensitivity loss in certain clinical populations can be gained.

（摘自申请人摘要）本研究的目的是 量化和经验评估明视检测和光的模型 适应 该实验结合了联合收割机两种研究方法， 明视敏感度：“适应”和“色觉”方法。 前者检查中心凹检测和适应与探针闪光 范例 增量阈值是针对一个简短的目标（ “探针”）呈现在闪烁的场（“闪光”）上，视觉 系统没有时间适应。 探测闪光技术揭示了 在稳定场中不明显的锥系统中的非线性。 在色觉方法中，最初制定的模型解释了 将颜色外观应用于灵敏度数据。 模型假设， 光的可探测性取决于它在三个方面引起的活动 通道或通道。 其中包括两个对手的半音阶通道 (red/绿色和黄色/蓝色）和一个非对手的消色差途径。 探头闪光数据已与包含单个静态 非线性虽然这些数据很容易被这样的模型描述， 视觉通路中的敏感性丧失仍不清楚。 精神病学家最初假设数据反映了非线性 在视锥细胞感受器中。 然而，各种措施表明， 在许多情况下，脱敏发生在受体之外， 涉及到幽灵般的对立机制 一个两个网站的模型被开发来解释后的证据， 探测闪光数据中的受体非线性。 本提案的一个目标是 是建立一个模型来预测变化对适应环境的影响 强度。 第二个目标是比较静态非线性 从心理学上推断出灵长类动物的生理学。 最近的录音 灵长类视锥细胞反应功能为直接 受体生理学和行为学之间的比较。 在长波长和短波长锥路径中的灵敏度将是 考察 后者提供了一个有价值的研究课题，因为它 相对易患视网膜疾病。 获得的探头闪光数据 这些患者对于观察到的 灵敏度的下降反映了受体或受体后缺陷。 通过 在正常观察者中分离受体和对手的非线性，以及 将结果与灵长类动物受体数据进行比较， 可以获得某些临床人群中灵敏度丧失的位点。