Neuronal Mechanisms for Working Memory in Prefrontal Cortex

描述（由申请人提供）：我们提出了一个合作的努力，以表征持续皮层活动的细胞和系统机制及其对大鼠工作记忆的贡献。该项目将利用微量眼睑调节（TEC）的优势，并将莫克实验室的系统神经科学专业知识与约翰斯顿实验室的细胞神经科学专业知识相结合。我们将利用几种新的方法来建立前额叶皮层（PFC）持续活动的细胞机制和工作记忆的系统机制之间的联系。莫克实验室已经证明，TEC需要从内侧（m）PFC到外侧脑桥（然后到小脑）的互连通路的持续活动，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锥体神经元亚群，该亚群投射到外侧脑桥。最后，在体外记录这些mPFC神经元从行为训练的动物已调查的细胞机制与行为的任务。这些和其他发现确立了TEC作为研究工作记忆相关行为的系统和细胞机制的特别易处理的手段。我们建议：1）使用局部注射的药物和多单位刺激和记录，以提供一个系统水平的分析持续放电，TEC，和工作记忆的行为大鼠; 2）使用局部注射在体内的重要ortho和逆行示踪剂，以确定TEC所需的途径。将根据数据构建这些通路的3D解剖图; 3）研究参与行为的这些通路中标记神经元的细胞和神经调节特性。后者的实验将完成使用全细胞和细胞贴附补丁记录和钙离子成像从PFC神经元在脑切片。该项目将允许对持续的皮层活动进行前所未有的分析，并显着提高治疗疾病相关的工作记忆缺陷的前景。

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.