STRUCTURE-FUNCTION RELATIONSHIPS IN VISUAL CORTEX

这项研究计划的长期目标是了解 作为信息处理基础的结构/功能关系 外侧膝状核(LGN)和视皮层。重点是 LGN在时间转换传入信号中的作用 来自视网膜，以及这些修改的信号对 感受野结构和视觉反应的产生 大脑皮层17区和18区神经元的特性。 实验发现，LGN的A板层含有两个 一组中继神经元，称为滞后细胞和非滞后细胞，它们不同 它们对视觉刺激做出反应的时间明显不同。我们有 有证据表明这些时差在视觉皮质中被用来设置 向上感受场的时空结构，并创造神经元 它们对刺激运动的方向很敏感。这个 拟议的实验将揭示脑内神经元的计时特性 膝状复合体的其他分支及其潜力 对皮质细胞的响应特性的贡献，并确定 LGN和大脑皮层的反应时序是否可以被异常改变 发育过程中的视觉刺激。 具体目标如下：(1)表征响应时间 膝状C板层和内侧板层内的中继神经元 细胞核(分钟)，以完成我们对膝状体的持续描述 皮质区17和18的输入。(2)检查 AIM细胞的形态和生理特性 1，作为阐明潜在的结构机制的基础 LGN中的信息处理。(3)揭开终点区 在不同膝曲细胞类型的皮质中，并寻找一种 传入类型和/或反应时序的板下分布 解释响应层流差异来源的依据 大脑皮层细胞间的时间。(4)刻画时空特征 单细胞感受野的结构和方向选择性 并将它们的反应时间与膝状体的反应时间进行比较 传入器。(5)调查饲养动物的影响。 频闪光照环境对细胞反应时序的影响 在LGN和(6和7)中关于接受者的时空结构 17区和18区的田野。有选择地取消频闪饲养 大脑皮质的方向选择性。响应时间的平行变化 这些动物的LGN和皮质之间的关系将提供进一步的证据 LGN在促进大脑皮层方向选择性中的作用。 这些研究还将提供有关机制的第一个详细证据。 在频闪饲养的动物中失去方向选择性的根本原因是， 从而有助于我们对以下基材的整体理解 方向选择性。

The long range goal of this research program is to understand the structure/function relationships that underlie information processing in the lateral geniculate nucleus (LGN) and visual cortex. Emphasis is on the role of the LGN in temporally transforming afferent signals derived from the retina, and on the contribution these modified signals make to the generation of receptive field structure and visual response properties of neurons in cortical areas 17 and 18. The impetus for the experiments is the finding that the A-laminae of the LGN contain two groups of relay neurons, termed lagged and nonlagged cells, which differ markedly in the timing of their responses to visual stimuli. We have evidence that these timing differences are used in visual cortex to set up the spatiotemporal structure of receptive fields and to create neurons that are sensitive to the direction of stimulus movement. The experiments proposed will reveal the timing properties of neurons in other divisions of the geniculate complex and their potential contribution to the response properties of cortical cells, and determine whether response timing in the LGN and cortex can be modified by abnormal visual stimulation during development. Specific aims are as follows: (1) To characterize the response timing of relay neurons in the geniculate C-laminae and the medial interlaminar nucleus (MIN) in order to complete our ongoing description of geniculate inputs to cortical areas 17 and 18. (2) To examine relationships between the morphological and physiological properties of cells examined in Aim 1, as a basis for elucidating structural mechanisms underlying information processing in the LGN. (3) To reveal the termination zones in cortex of different geniculate cell types, and to search for a sublaminar distribution of afferent types and/or response timing as a basis for interpreting the origin of laminar differences in response timing among cortical cells. (4) To characterize the spatiotemporal structure and direction selectivity of simple cell receptive fields in area 18 and to compare their response timing with that of the geniculate afferents. (5) To investigate the impact of raising animals in a stroboscopically illuminated environment on the response timing of cells in the LGN and (6 and 7) on the spatiotemporal structure of receptive fields in areas 17 and 18. Strobe rearing selectively abolishes direction selectivity in cortex. Parallel changes in response timing between LGN and cortex in these animals will provide further evidence for the role of the LGN in contributing to direction selectivity in cortex. These studies will also provide the first detailed evidence on mechanisms underlying the loss of direction selectivity in strobe-reared animals, and hence contribute to our overall understanding of the substrates for direction selectivity.