The behavioral functions of upper and lower cortical layers

项目总结/摘要 大脑皮层调节着人类和动物的所有认知，包括各种各样的能力 包括感觉、知觉、决策和运动规划。大脑皮层功能障碍 被认为是许多神经和精神疾病的基础。一个主要的障碍， 正常的行为和治疗病理是高度复杂的皮层电路， 仍然是个谜新皮层的传统观点认为，感觉处理始于大脑皮层。 层4（L4），世纪前被确定为丘脑轴突携带信息的主要目标 从我们的感觉器官。人们普遍认为，当兴奋连续地沿着 致密轴突通路（丘脑→L4→L2/3→L5/6）。最近我们发现大脑皮层， 而不是单片结构，可以包含两个完全独立的处理系统， 同样的信号来自丘脑因此，L4不是皮质活动的强制性分布中心， 丘脑平行地激活两个不同的皮层“层”。 本提案的目标是确定上层（L2-4）和下层的行为和计算角色 层（L5/6）以及它们之间的相互作用。我们将研究这些层的行为角色 在鼠标胡须系统中。特定的层将在一系列触觉行为中被光遗传学破坏。 任务，其中任务的复杂性逐渐增加。层间相互作用也将研究， 在行为期间从特定层记录电生理学并使用新的机器学习 旨在识别在不同级别的“深度网络”中执行的计算类型的技术。的 将在正常行为下估计层中表示的维度， 层被灭活。 确定上层与皮层的基本功能可能会为未来的研究铺平道路。 在其他新皮层系统和高阶物种中的研究。此外，由于不同层包含 分子和生物物理上不同的细胞类型，并投射到不同的下游靶点，特定的 神经障碍可能涉及特定途径、细胞类型和细胞层的功能障碍。建立 这些元素的行为和计算作用可能有助于靶向治疗的发展。

PROJECT SUMMARY/ABSTRACT The cerebral cortex mediates all of human and animal cognition, encompassing a diverse set of abilities including sensation, perception, decision making, and motor planning. Dysfunctions of the cerebral cortex are thought to underlie numerous neurological and psychiatric disorders. A major obstacle both to understanding normal behaving and to treating pathology is the high degree of complexity of cortical circuitry, which has remained largely enigmatic. The conventional view of neocortex has been that sensory processing begins in layer 4 (L4), which was identified a century ago as the principal target of thalamic axons carrying information from our sensory organs. Sensory transforms are widely believed to occur as excitation spreads serially along the densest axonal pathways (thalamus→L4→L2/3→L5/6). Recently we discovered that the cerebral cortex, rather than being a monolithic structure, may contain two entirely separate processing systems, activated by the same signals arising from the thalamus. L4 is thus not an obligatory distribution hub for cortical activity, and thalamus activates two distinct “strata” of cortex in parallel. This proposal's goal is to identify the behavioral and computational roles of the upper (L2-4) and lower strata (L5/6) as well as the interactions between them. We will investigate the behavioral roles of these layers in the mouse whisker system. Specific layers will be optogenetically disrupted in a series of tactile behavioral tasks, in which task complexity is progressively increased. Interlaminar interactions will also be studied by recording electrophysiologically from specific layers during behavior and using novel machine learning techniques designed to identify the type of computation performed in different levels of “deep networks”. The dimensionality of the representation in a layer will be estimated under normal behaviors and when specific layers are inactivated. Identifying fundamental functions of upper versus cortical layers will likely pave the way for future studies in other neocortical systems and in higher-order species. Moreover, as the different layers contain molecularly and biophysically distinct cell types and project to distinct downstream targets, specific neurological disorders may involve dysfunction of specific pathways, cell types, and layers. Establishing the behavioral and computational roles of these elements may contribute to development of targeted therapies.