A universal and 3D-printed rat calvarium replacement system to enable for pan-cortical and sub-cortical recordings and optogenetics

摘要 虽然大范围的脑动力学改变是重度抑郁症（MDD）的关键脑特征， 尽管在啮齿类动物身上有太多强大的神经科学工具，但我们目前实际上还没有 在啮齿类动物中，用突触时间尺度的时间和 单神经元分辨率这是神经科学家研究MDD相关生物学能力的一个关键差距， 啮齿动物模型，包括持续威胁模型。电生理学和光遗传学方法将是 理想的研究新皮质动力学是如何在基线编排，并在疾病中受到干扰，因为许多 这些机制本质上可以是突触的，并且两种方法都可以在突触时间尺度上操作。我们是一个团队 我们的目标是开发一个系统，允许植入以前- 不切实际的电极和光纤的复杂组合来记录和操纵老鼠的大脑。的 我们的方法的基础是一个三维打印（3D打印）的背侧大鼠头骨替代品-一个“接口” “板”-我们已经成功地连接到两个老鼠与良好的生存。与天然头骨不同， 接口板是定制设计和制造的，因此可用于引导和固定许多器械， 该动物使用包括手术前组装的新型手术方法。我们的目标是优化设计， 界面板，使两个实验，这将是新颖的和关键的研究持续的威胁有关的 新皮层动力学紊乱第一个目标将使用我们的3D打印定位和引导系统来放置 128个电极遍布整个背部新皮层。这将使有史以来第一次绘制的电气 整个背侧新皮层的亚毫秒分辨率的活动，使我们能够捕捉到 从突触传递到振荡，再到神经调节、行为和大脑状态转换。我们将 此外，在表层和深层放置电极，以收集关于这些电极的相对作用的数据。 进化上保守的解剖层。在第二个目标中，我们将调整我们的接口板，以实现记录 同时记录和光遗传学刺激在新皮层中起关键作用的区域， 协调新皮层，包括背侧海马、丘脑内侧背核（MDN）和 丘脑网状核（TRN）。在这个目标中，8个（后来是32个）电极将被植入皮层， 在背侧海马CA 1区、MDN区和TRN区植入硅探针，记录64 通道和耦合光纤。这将有助于实验检查和测试的作用， 新皮层结构在协调皮层在持续的威胁条件下。实验 在这里启用将提供关于健康和疾病的新皮层的基本新数据。这项工作将 也导致创建一个可定制的和灵活的新工具，我们将公开提供，使 在行为自由的动物身上进行的复杂实验。

Abstract While altered broad-scale brain dynamics are a key brain signature of major depressive disorder (MDD) and despite the plethora of powerful neuroscientific tools available in rodents, we actually do not currently have the capacity to assess these broad-scale neocortical dynamics in rodents with synaptic-timescale temporal and single neuron resolution. This is a key gap in the capacity of neuroscientists to study MDD-related biology via rodent models including the sustained threat model. Electrophysiologic and optogenetic approaches would be ideal to study how neocortical dynamics are orchestrated at baseline and are perturbed in disease, since many mechanisms may be synaptic in nature and both methods can operate at synaptic-timescales. We are a team of neuroscientists and mechanical engineers and we aim to develop a system to allow implantation of previously- impractical complex combinations of electrodes and optic fibers to record and manipulate the rat brain. The basis of our approach is a 3-dimensionally printed (3D printed) replacement for the dorsal rat skull – an “Interface Plate” - which we have already successfully attached to two rats with good survival. Unlike a natural skull the Interface Plate is custom designed and fabricated and so can be adapted to guide and secure many devices to the animal using a novel surgical approach including pre-surgical assembly. We aim to optimize our design for the Interface Plate to enable two experiments that will be novel and crucial to studies of sustained threat-related disturbances in neocortical dynamics. The first aim will use our 3D printed positioning and guide system to place 128 electrodes broadly across the entire dorsal neocortex. This will enable the first ever mapping of electrical activity at sub-millisecond resolution across the entire dorsal neocortex enabling us to capture events ranging from synaptic transmission to oscillations to neuromodulation, behavior and brain state transitions. We will additionally place electrodes at both superficial and deep layers to gather data about relative roles of these evolutionarily-conserved anatomical layers. In a second aim we will adapt our Interface Plate to enable recording in neocortex while simultaneously recording and optogenetically stimulating regions that play key roles in coordinating neocortex including the dorsal hippocampus, the medial dorsal nucleus of the thalamus (MDN) and the thalamic reticular nucleus (TRN). In this aim, 8 (and later 32) electrodes will be implanted in cortex for recording while into dorsal hippocampal CA1, MDN and TRN we will implant silicon probes with 64 recording channels and a coupled optic fiber. This will facilitate experiments examining and testing the roles of non- neocortical structures in coordinating the cortex both in and out of sustained threat conditions. The experiments enabled here will provide fundamental new data regarding the neocortex in health and disease. This work will also lead to the creation of a customizable and flexible new tool which we will make openly available to enable complex experiments in freely behaving animals for anyone in the neuroscience community.