Neuronal Mechanisms for Working Memory in Prefrontal Cortex

描述（由申请人提供）：我们提出了一项合作研究，以表征大鼠持久皮层活动的细胞和系统机制及其对工作记忆的贡献。该项目将利用眼皮追踪调节（TEC）的优势，并结合莫克实验室的系统神经科学专业知识和约翰斯顿实验室的细胞神经科学专业知识。我们将利用几种新的方法来建立前额皮质（PFC）持续活动的细胞机制与工作记忆的系统机制之间的联系。Mauk实验室已经证明，TEC需要一个从内侧(m) PFC到外侧脑桥（然后到小脑）的相互连接通路的持续活动，这是TEC所需的。约翰斯顿实验室在体内注射了重要的逆行示踪剂（Lumafluor珠），以在体外鉴定mPFC中具有独特电生理特性的L5金字塔状神经元亚群，该亚群投射到侧脑桥。最后，对行为训练动物的这些mPFC神经元进行体外记录，以研究与行为任务相关的细胞机制。这些发现和其他发现使TEC成为研究工作记忆相关行为的系统和细胞机制的一种特别容易处理的方法。我们建议1)使用局部注射药物和多单元刺激和记录来提供行为大鼠持续放电、TEC和工作记忆的系统级分析；2)在体内局部注射重要的正、逆行示踪剂，以确定TEC所需的通路。将根据数据构建这些通路的三维解剖图；3)研究这些通路中参与行为的标记神经元的细胞和神经调节特性。后一项实验将使用全细胞和细胞贴片记录和脑切片PFC神经元的Ca2+成像来完成。该项目将允许对持续皮层活动进行前所未有的分析，并显著提高治疗工作记忆疾病相关缺陷的前景。

DESCRIPTION (provided by applicant): We propose a collaborative effort to characterize the cellular and systems mechanisms of persistent cortical activity and its contributions to working memory in the rat. The project will leverage the advantages of trace eyelid conditioning (TEC) and combine the systems-neuroscience expertise of the Mauk lab with the cellular- neuroscience expertise of the Johnston lab. We will utilize several novel approaches designed to establish links between the cellular mechanisms of persistent activity in prefrontal cortex (PFC) and the systems mechanisms of working memory. The Mauk lab has demonstrated that TEC requires persistent activity of an interconnected pathway from medial (m) PFC to lateral pons (and then to cerebellum) that is required for TEC. The Johnston lab has injected vital retrograde tracers (Lumafluor beads) in vivo to identify in vitro a subpopulation of L5 pyramidal neurons in mPFC with unique electrophysiological properties that projects to the lateral pons. Finally, in vitro recordings from these mPFC neurons from behaviorally trained animals have been made to investigate the cellular mechanisms associated with the behavioral task. These and other findings establish TEC as an especially tractable means to study the systems and cellular mechanisms of a working- memory-related behavior. We propose 1) to use local injections of pharmacological agents and multiunit stimulation and recordings to provide a systems-level analysis of persistent firing, TEC, and working memory in the behaving rat; 2) to use local injections in vivo of vital ortho- and retrograde tracers to determine the pathways required for TEC. A 3D anatomical map of these pathways will be constructed from the data; and 3) to investigate the cellular and neuromodulatory properties of labeled neurons in these pathways that participate in the behavior. The latter experiments will be accomplished using whole-cell and cell-attached patch recordings and Ca2+ imaging from PFC neurons in brain slices. This project should permit an unprecedented analysis of persistent cortical activity and significantly enhance the prospects for treating disease-related deficits in working memory.