PERIODIC INTRINSIC CONNECTIONS IN VISUAL CORTEX

灵长类区域17的水平纤维带出现在I、IVB层(也 称为IIIC)和V，并且在很大程度上由本征 关系。我们实验室最近的研究表明，定期 树鼠纹状皮质内有组织的内在联系， 松鼠、猴子和猕猴。在皮质内注射HRP后， 这些周期性在颗粒上层中表现得尤为突出。(i-iii)。 在猴子中，在IVB层和IVB层中发现了更多的周期性连接 这些内在的解剖联系以前从未出现过 描述。它们的规则几何图案让人强烈地联想到 皮质活动的生理和代谢模式；以及这些 因此，解剖学上的联系提出了有趣的含义，即 功能属性(如定向特性、双目或 复杂的接受场属性)可以在内部详细阐述。 纹前皮质的固有联系也存在周期性模式。 (V2区和V4区)，以及纹状和 纹前皮质。对这些相互关系的系统分析是 与有关功能和结构的基本问题相关 视觉皮质的组织。例如，出现多个， 层流特有的内在格子状连接对这一概念提出了质疑 径向柱或模块作为新皮质的唯一构建块 这表明水平的椎板内连接也很重要。这个 拟议的调查将集中在1)提供详细的灯光 纹状皮质内固有周期性联系的微观描述 在几个纹状体前区域(通过HRP或~3H-氨基酸 注射)，2)分析选定的配对之间的关系 超颗粒内的本征和非本征周期连接 纹状体和纹前皮质中的各层(通过两个解剖学方法 结合使用的示踪剂)，以及3)启动超微结构研究， 重点是HRP充满神经元的突触后接触 在17区的超颗粒连接格子内。希望 这些数据将增加我们对正在进行的大脑皮质过程的理解 超过IV层，包括随后到纹前皮质的中继站，以及 提供了一些关于高级视觉处理机制的线索。

Horizontal fiber bands in primate area 17 occur in layers I, IVB (also termed IIIC) and V, and are composed in large measure of intrinsic connections. Recent studies in our laboratory have revealed periodically organized intrinsic connections within striate cortex of tree shrews, squirrel monkeys, and macaque. After intracortical injections of HRP, these periodicities are prominent in the supragranular layers. (I-III). In monkey, further periodic connections are found within layers IVB and VI. These intrinsic anatomical connections have not been previously described. Their regular geometric pattern is strongly reminiscent of physiological and metabolic patterns of cortical activity; and these anatomical connections thus raise interesting implications for how functional properties (such as orientation specificity, binocularity, or complex receptive field attributes) may be elaborated intracortically. Periodic patterns also occur in intrinsic connections of prestriate cortex (areas V2 and V4), and in several extrinsic connections of both striate and prestriate cortex. Systematic analysis of these interrelationships is relevant to basic questions concerning the functional as well as structural organization of visual cortex. For instance, the occurrence of multiple, laminar-specific, intrinsic lattice-like connections questions the concept of radial columns or modules as the sole building blocks of neocortex and suggests that horizontal intralaminar connections are also important. The proposed investigations will concentrate on 1) providing a detailed light microscopic description of intrinsic periodic connections in striate cortex and in several prestriate areas (by means of HRP or 3H-amino acid injections), 2) analysing the relationship between selected pairs of intrinsic and extrinsic periodic connections within the supragranular layers, both in striate and prestriate cortex (by means of two anatomical tracers used in combination), and 3) initiating ultrastructural studies, with emphasis on the post-synaptic contacts made by HRP-filled neurons within the supragranular connectional lattice in area 17. It is hoped that these data will increase our understanding of cortical processes going on beyond layer IV, including subsequent relays to prestriate cortex, and provide some clues as to mechanisms of higher visual processing.