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努力，以表征持续皮质活动的细胞和系统机制及其对大鼠工作记忆的贡献。该项目将利用痕迹眼皮调节(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质(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。Mauk实验室已经证明，TEC需要一条从内侧(M)PFC到外侧桥(然后到小脑)的相互连接的通路的持续活动，这是TEC所必需的。约翰斯顿实验室在体内注射了重要的逆行示踪剂(Lumafluor珠子)，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，这些神经元投射到侧脑桥。最后，对这些来自行为训练动物的mPFC神经元进行了体外录音，以研究与行为任务相关的细胞机制。这些和其他发现确定了TEC是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手段。我们建议1)使用局部注射药物和多单位刺激和记录来提供对行为大鼠持续放电、TEC和工作记忆的系统水平的分析；2)使用体内局部注射重要的正位和逆行示踪剂来确定TEC所需的通路。将根据这些数据构建这些路径的3D解剖图；以及3)研究参与行为的这些路径中标记的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附的贴片记录以及大脑切片中PFC神经元的钙成像来完成。该项目应该能够对持续的大脑皮层活动进行前所未有的分析，并显著增强治疗与疾病相关的工作记忆缺陷的前景。 与公共健康相关：工作记忆过程有助于广泛的认知过程，工作记忆缺陷与一系列与年龄和疾病相关的认知功能障碍有关。这些疾病包括阿尔茨海默氏症、注意力障碍，如ADHD、自闭症和精神分裂症，以及各种其他学习障碍。

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. PUBLIC HEALTH RELEVANCE: Working memory processes contribute to a wide variety of cognitive processes, and working memory deficits are associated with a host of age- and disease-related cognitive dysfunction. These include Alzheimer's disease, attentional disorders such as ADHD, autism, and schizophrenia, as well as a variety of other learning disabilities.