DEVELOPMENT OF COMPLEX RETINAL FIELDS

这项拟议研究的长期目标是了解 处理过程有助于图像信息处理的发展 胚胎和新生动物的视网膜。这项基础研究可能 对未来人类遗传性疾病的治疗具有重要意义 视网膜。为达到研究目的，提出了一种理论上的 框架被提出，它展示了树枝状生长，光照， 和自发的活动波(未成熟的孤立视网膜常见， 但尚未在体内进行研究)可促进 视网膜信息处理。提出的具体问题如下： 1)发育中的视网膜在体内有自发波活动吗？如果 那么，这项活动的性质是什么呢？要回答这些问题， 发育中的海龟的眼睛将用两个电极记录 同时用一种新的数学方法对结果进行了分析。 这些实验将在正常条件下进行，并在视觉上- 以及药理上不正常的。然后将数据与 在理论框架下进行了计算机模拟。 2)是由细胞外钾介导的自发波 胆碱能突触？为了回答这个问题，一种新的技术 将使用神经节细胞中的光学成像钙离子。这项技术 将允许获得横跨细胞的波的时空分布以及 因此，为了检验这些波的最新模型所做的预测。在……里面 特别是，这个模型预测了新斯的明的效果， 胆碱酯酶抑制剂Cs和TEA，两种K电流阻滞剂，以及二氧化碳， 一种突触阻滞剂。 3)自发活动是否有助于发展接受性-- 场大小和取向选择性？测试海浪是否会对 对于这些特性的发展，一种植入技术 眼内一种聚合物，可以缓慢地释放与之混合的药物 是发展起来的。在拟议的实验中，这些药物将是新斯的明 和二氧化碳。定向选择性与感受野大小的关系 将作为年龄的函数来测量这些条件中的每一种 结果与新的计算机模拟结果进行了比较。

The long-term objective of the proposed research is to understand what processes contribute to the development of image information processing in the retinas of embryos and neonatal animals. This basic research could have important implications for future cure of genetic diseases of the retina. To achieve the objectives of the research, a theoretical framework was proposed, which shows how dendritic growth, light exposure, and spontaneous waves of activity (common to immature isolated retinas, but as yet not studied in vivo) can contribute to the development of retinal information processing. The specific questions being asked are: 1) Do developing retinas have spontaneous waves of activity in vivo? If so, what are the properties of this activity? To answer these questions, the eyes of developing turtles will be recorded with two electrodes simultaneously and the results analyzed with a new mathematical technique. The experiments will be performed under normal conditions and visually- and pharmacologically-abnormal ones. The data will then be compared to computer simulations performed with the theoretical framework. 2) Are spontaneous waves mediated by extracellular potassium and cholinergic synapses? To answer this question, a new technique for optically imaging Ca2+ in ganglion cells will be used. This technique will allow to obtain the waves' spatio-temporal profile across cells and thus, to test the predictions made by a recent model of these waves. In particular, this model predicts the effects of neostigmine, a cholinesterase inhibitor, Cs+ and TEA, two K+-currents blockers, and Co2+, a synaptic blocker. 3) Does spontaneous activity contribute to the development of receptive- field size and orientation selectivity? To test whether waves contribute to the development of these properties, a technique to implant intraocularly a piece of polymer that slowly releases drugs mixed with it was developed. In the proposed experiments, the drugs will be neostigmine and Co2+. Incidence of orientation selectivity and receptive-field size will be measured for each of these conditions as a function of age, and the results compared to those of new computer simulations.