The behavioral functions of upper and lower cortical layers

项目摘要/摘要 大脑皮层调节人类和动物的所有认知，包括一系列不同的能力 包括感觉、知觉、决策和运动规划。大脑皮层功能障碍是 被认为是许多神经和精神疾病的基础。一个主要的障碍既是理解 正常的行为和对病理的治疗是皮质回路的高度复杂，它具有 这在很大程度上仍然是个谜。对新皮质的传统观点认为，感觉处理始于 第四层(L4)，一个世纪前被确定为丘脑轴突传递信息的主要目标 从我们的感官器官。人们普遍认为，当兴奋连续传播时，感觉变化就会发生。 最密集的轴突通路(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，由 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，并且 丘脑同时激活两个不同的皮质“层”。 该提案的目标是确定上层(L2-4)和下层(L2-4)的行为和计算角色 地层(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 在老鼠胡须系统中。在一系列触觉行为中，特定的层将被光基因扰乱 任务，其中任务的复杂性逐渐增加。层间相互作用也将通过以下方式研究 在行为过程中从特定层记录电生理并使用新的机器学习 旨在识别在不同级别的“深层网络”中执行的计算类型的技术。这个 在正常行为下和在特定情况下，将估计图层中表示的维度 层处于停用状态。 确定上层与皮质层的基本功能可能为未来铺平道路 在其他新皮质系统和更高级物种中的研究。此外，由于不同的层包含 在分子和生物物理上不同的细胞类型和投射到不同的下游靶点，特定的 神经功能障碍可能涉及特定的通路、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.