Layer-specific encoding of working memory in an automated 8-arm radial maze

项目摘要/摘要 工作记忆(WM)是允许暂时存储和处理信息的认知实体。 对于赋予生命主观意义的许多东西来说，情感是至关重要的，并使个人能够参与更大的 社会。这包括跟踪对话、寻找超市商品、计划、驾驶、学习新知识 技能--几乎任何需要记住来自长期记忆和/或感觉输入的信息的东西 使用需要WM。因此，WM功能障碍具有毁灭性的影响，令人遗憾的是，数百万人 患有精神分裂症、抑郁症、多动症、痴呆症等--经历不同程度的WM损害， 几乎完全对治疗产生抗药性。鉴于它在神经认知健康和疾病中的作用，理解 WM机制的研究势在必行。相应地，本项目将深入探索WM的电路基础。 前额叶皮质(PFC)被认为是WM的主要协调者，处理来自其他大脑的输入 WM实例化的区域。在空间工作记忆(SWM)中，经常被研究的WM子域 PFC与腹侧海马和丘脑内侧背核(MD)的种类、相互作用 被认为是必不可少的，PFC-MD的相互作用支持WM内容和WM的神经维持 后续操作选择。值得注意的是，PFC是非常不同的，由不同的层组成 在它们的细胞组成和连接性上。然而，这些层状亚区可能 为PFC授权WM的多方面方式做出独特贡献直到现在才被探索：最近 研究表明，浅层PFC层支持WM内容维护，而深层PFC层支持WM内容维护 维护后操作选择。这项建议通过使用新技术来扩展这些研究 探索WM中的细胞分辨率层流表示。 具体地说，这项建议检查了在单个细胞与群体的活动中编码了哪些WM内容- TIONS在不同的PFC层中(目标1)，并评估这些层流WM表示对 来自MD的输入(目标2)。为此，将通过显微内窥镜在小鼠身上进行钙成像 基因和外科手术指定的表达钙指示剂，特别是PFC层。这些老鼠会 执行基于试验的延迟不匹配，以在定制的自动化八臂径向迷宫中采样WM任务， 对于Aim 2，将在行为和成像期间将MD输入光遗传地静默到PFC(以模拟 在WM缺陷者中经常观察到MD-PFC连接不足)。最后，为了严格映射 从行为到神经活动，将使用新的机器学习行为分类范例。 WM为日常生活中维系社会关系的结构提供了认知基础， 保住工作，独立生活，学习新事物等等。鉴于这样的复杂性，详细的 需要询问WM电路机制。因此，该提案使用新兴技术来 探索西医功能和功能障碍的电路机制，推动治疗创新的追求。

PROJECT SUMMARY / ABSTRACT Working memory (WM), the cognitive entity that allows for temporary storage and manipulation of informa- tion, is crucial for much of what gives life subjective meaning, and enables an individual to participate in larger society. This includes following a conversation, finding a supermarket item, planning, driving, learning new skills—most anything that requires holding in mind information from long-term memory and/or sensory input for use requires WM. As a result, WM dysfunction has devastating effects, and regrettably, millions—individuals with schizophrenia, depression, ADHD, dementia, and more—experience varying degrees of WM impairment, which is almost totally treatment resistant. Given its role in neurocognitive health and disease, understanding the mechanisms of WM is imperative. Correspondingly, this project will explore in depth the circuit basis for WM. The prefrontal cortex (PFC) is known to be a primary orchestrator of WM, processing input from other brain regions for WM instantiation. In spatial working memory (SWM), a WM subdomain regularly studied across species, interactions of the PFC with the ventral hippocampus and mediodorsal nucleus of the thalamus (MD) are considered essential, with PFC-MD interactions undergirding neural maintenance of WM content and subsequent action selection. Notably, the PFC is quite heterogeneous, being composed of layers that differ both in their cellular composition and in their connectivity. Yet the possibility that these laminar subregions might uniquely contribute to the multifaceted ways in which the PFC empowers WM is only now being explored: recent studies suggest that superficial PFC layers support WM content maintenance, while deep PFC layers support post-maintenance action selection. This proposal expands upon these studies by using novel technology to explore cellular-resolution laminar representations in WM. Specifically, this proposal examines what WM content is encoded in the activity of individual cells vs. popula- tions in the different PFC layers (Aim 1) and assesses the dependence of these laminar WM representations on input from the MD (Aim 2). To do so, calcium imaging will be performed through microendoscopes in mice genetically and surgically specified to express calcium indicators in particular PFC layers. These mice will perform a trial-based delayed nonmatch to sample WM task in a custom-built, automated 8-armed radial maze, and for Aim 2 will have MD input to the PFC optogenetically silenced during behavior and imaging (to simulate the MD-PFC hypoconnectivity regularly observed in those with WM deficits). Finally, for rigorous mapping of behavior to neural activity, novel machine learning behavioral classification paradigms will be used. WM provides the cognitive building blocks for the very fabric of quotidian life—sustaining social relationships, maintaining a job, living independently, learning new things and more. Given such complexity, detailed interrogation of WM circuit mechanisms is required. Accordingly, this proposal uses emerging technologies to explore circuit mechanisms of both WM function and dysfunction, advancing pursuits of therapeutic innovation.