STRUCTURE FUNCTION RELATIONSHIPS IN VISUAL CORTEX

这项研究计划的长期目标是了解 结构/功能关系，这些关系是处理 信息进出视觉皮层 拟议的实验 这里讨论的问题，传入输入到17和18区， 来自猫的外侧膝状体核（LGN）。 是我最近的解剖学发现， 区域17的第IV层中的单个X细胞和Y细胞轴突与 视网膜细胞索马体在膝状体A板内的位置 (i.e.,层A和A1）。 目前的目标是了解功能 这种位置和投影关系的重要性，无论是在 LGN和区域17内，并确定是否类似 在向18区的膝状皮质投射中保持联系。 具体目标如下：（1）确定X细胞和Y细胞的 一个细胞的位置与其深度之间存在关系。 A-纤层及其功能特性。 使用的方法将是细胞外的 视觉响应特性的记录和定量分析（即， 时空频率调谐，峰值对比敏感度，潜伏期 和视觉刺激的放电模式）。 将使用类似的测试 以表征C层和内侧层间核中的Y细胞 （MIN）。 (2)为了确定椎板下投影的差异 X-和Y-细胞轴突在第IV和第VI层的区域17反映的差异， 细胞的视觉反应特性。 单个膝状皮质轴突将 记录在视觉皮层中，它们的视觉共振特性将被 它们将通过细胞内注射 辣根过氧化物酶显示它们在皮层中轴突终末的分支 及其位于LGN中的细胞体。 Y细胞层下投射 还将检查区域18中的轴突。 (3)以确定是否 投射到区域18的Y细胞的视觉反应特性不同于 Y细胞投射到17区。 (4)为了确定椎板下 来自小细胞C板层的W细胞轴突的投射 LGN。 所获得的结果将揭示组织的基本规则， 猫的膝状皮质投射，并导致更好的理解 这种视觉信息分布在大脑皮层细胞中， 17和18区内的不同亚层。

The long range goal of this research program is to understand structure/function relationships that underlie the processing of information into, through, and out of visual cortex. Experiments proposed here address questions about the afferent input to areas 17 and 18 that arises from the lateral geniculate nucleus (LGN) in the cat. The impetus for the experiments is my recent anatomical finding that the sublaminar of single X- and Y-cell axons in layer IV of area 17 are strongly related to retinal cells' soma positions within the depths of the geniculate A-laminae (i.e., lamina A and Al). The present goal is to understand the functional significance of this positional and projectional relationship, both within the LGN and within area 17, and to determine whether analogous relationships hold in the geniculocortical projections to area 18. Specific aims are as follows: (1) To determine for X- and Y-cells what relationship exists between a cell's position within the depth of its A-lamina and its functional properties. Methods used will be extracellular recording and quantitative analysis of visual response properties (viz., spatial and temporal frequency tuning, peak contrast sensitivity, latency and discharge pattern to visual stimulation). Similar tests will be used to characterize Y-cells in lamina C and the medial interlaminar nucleus (MIN). (2) To determine whether differences in the sublaminar projections of X- and Y-cell axons in layer IV and VI of area 17 reflect differences in the cell's visual response properties. Single geniculocortical axons will be recorded in visual cortex, their visual resonse properties will be identified, and they will be labeled by intracellular injections of horseradish peroxidase to visualize their axon terminal arbors in cortex and their cell bodies in the LGN. The sublaminar projections of Y-cell axons in area 18 will also be examined. (3) To determine whether the visual response properties of Y-cells projecting to area 18 differ from those of Y-cells projecting to area 17. (4) To determine the sublaminar projections of W-cell axons arising from the parvocellular C-laminae of the LGN. The results obtained will reveal basic rules of organization in the geniculocortical projections in the cat, and lead to a better understanding of the type of visual information which is distributed to cortical cells in different sublaminae within areas 17 and 18.