Cortical feedback microcircuits in the visual system of the mouse.

小鼠视觉系统中的皮质反馈微电路。

• 批准号: 203702-2013
• 负责人: Boire, Denis
• 金额: $ 1.82万
• 依托单位: Université du Québec à Trois-Rivières
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569991
• 关键词: Cortical; feedback; microcircuits; visual; system

Integrated perception of the outside world emerges from the processing of sensory information in multiple areas of the cerebral cortex. It is generally believed that the multiple cortical areas are reciprocally interconnected by an intricate network of feedforward and feedback connections. Forward connections provide information from lower to higher areas for further (bottom-up) processing. Feedback connections send information from higher areas and modulate lower areas activity (top-down). From these types of connections a general hierarchical model of cortical processing has been proposed and has been applied to primates, cats and rodents. These types of cortical connections are defined by the distribution of the cells of origin and their terminal axons in the 6 layers of the cerebral cortex. This gross pattern of laminar distribution of axonal terminals is the result of the sum of a host of single axons. Observations of single axons show a variety of termination patterns some of which are common to both forward and backward connections. There is yet no in depth understanding of the microcircuits that constitute these cortical macrocircuits. The classical model of hierarchical cortical networks has recently been challenged and the cerebral cortex is now more perceived as a distributed rather than a hierarchical network. It is increasingly evident that a dichotomous classification of cortical connections cannot account for the broad spectrum of connection types. At a local level, there is clear evidence for cortical microcircuits that reflect the long range target of axons to cortical and subcortical structures. The objective of the present proposal is a study of the fine structure of corticocortical connections at the single axon level in order to define the building blocs of these connection patterns. In doing this, we will have the basis to devise a novel classification of cortical connection that will account for their diversity. We will also provide basic knowledge of how these long range cortical connections are related to local microcircuits.

对外界的综合感知来自大脑皮层多个区域对感觉信息的处理。一般认为，多个皮层区域通过复杂的前馈和反馈连接网络相互连接。前向连接提供从较低区域到较高区域的信息，以便进一步（自下而上）处理。反馈连接从更高的区域发送信息，并调节较低区域的活动（自上而下）。从这些类型的连接的一般层次模型的皮层处理已被提出，并已被应用于灵长类动物，猫和啮齿动物。这些类型的皮质连接由大脑皮质的6层中的起源细胞及其末端轴突的分布来定义。这种轴突终末的层状分布的总体模式是许多单个轴突的总和的结果。单轴突的观察显示出各种各样的终止模式，其中一些是共同的向前和向后连接。目前还没有深入了解的微电路，构成这些皮层宏电路。分层皮层网络的经典模型最近受到了挑战，大脑皮层现在更多地被认为是一个分布式网络，而不是一个分层网络。越来越明显的是，皮质连接的二分法分类不能解释广泛的连接类型。在局部水平上，有明确的证据表明，皮层微电路反映了轴突到皮层和皮层下结构的长距离目标。本提案的目的是在单个轴突水平上研究皮质皮质连接的精细结构，以定义这些连接模式的构建块。 这样做，我们就有了设计一种新的皮层连接分类的基础，这种分类将解释它们的多样性。我们也将提供这些长距离皮层连接如何与局部微电路相关的基本知识。