DEVELOPMENT OF PHOTORECEPTOR FUNCTION

描述(改编自《调查者摘要》)：总体目标 是研究未成熟的视杆和视锥中的光传导过程 人类婴儿的光感受器。正常足月出生的婴儿 视网膜电图(ERG)反应的横断面研究 全场刺激将研究视杆细胞中的光传导失活 和锥体光感受器的激活。具体地说，视杆分离ERG 对两次闪光的反应将检验这样一种假设，即 婴幼儿视杆感光反应时相低于成人 控制。4周龄、10周龄和18周龄婴幼儿和成人的锥体细胞研究 控制将检验锥体的增益或灵敏度的假设 光传导的发育过程比饱和的 幅度。近中心出人意料的快速发展，杆状中介 视觉敏感度导致假设时间总和将是 偏心10度时成熟，偏心30度时不成熟。一个 心理物理程序和受试者内的设计将评估时间 10周和6个月龄婴儿10度和30度偏心的总和 老人和成人对照。 这项工作的长期目标是勾勒出 婴儿视网膜疾病中的视网膜功能障碍和视力损害， 将继续研究以前的早产儿，有一半的历史 非瘢痕性早产儿视网膜病变(ROP) ROP。杆状反应的激活和恢复阶段的ERG研究， 锥体反应将在后条款年龄进行，以检验假设 关于光感受器的机制。视觉的纵向测量 10度和30度偏心的阈值将测试 假设近中心阈值有一个异常缓慢的过程 有ROP病史的人的发展。

DESCRIPTION (Adapted from the Investigator's Abstract): the broad objective is to study phototransduction processes in the immature rod and cone photoreceptors of human infants. In normal term born infants cross-sectional studies of electroretinographic (ERG) responses to full-field stimuli will investigate phototransduction deactivation in rod and activation in cone photoreceptors. Specifically, rod isolated ERG responses to pairs of flashes will test the hypothesis that the recovery phase of the rod photoreceptor response is lower in infants than adult controls. The cone study in 4-, 10-and 18-week old infants and adult controls will test the hypothesis that the gain, or sensitivity, of cone phototransduction has a faster developmental course than does the saturated amplitude. The unexpectedly rapid development of near central, rod mediated visual sensitivity leads to the hypothesis that temporal summation will be mature at 10 degree eccentric while immature at 30 degree eccentric. A psychophysical procedure and a within subject design will assess temporal summation at 10 degree and 30 degree eccentricities in 10 week olds, 6 month olds and adult controls. The long term objective of this work, the delineation of mechanisms of retinal dysfunction and visual impairment in infantile retinal disorders, will be pursued with studies in former preterms, half with a history of non-cicatricial retinopathy of prematurity (ROP) and half with no history of ROP. ERG studies of the activation and recovery phases of the rod response, and cone responses will be conducted at post terms ages to test hypotheses about photoreceptor mechanisms. Longitudinal measures of the visual thresholds at 10 degree and 30 degree eccentricities will test the hypothesis that the near central threshold has an abnormally slow course of development in those with a history of ROP.