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

摘要 虽然改变的大范围脑动力学是严重抑郁障碍(MDD)和 尽管啮齿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 用突触-时间尺度和时间尺度评估啮齿动物的这些广泛的新皮质动力学的能力 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 是研究新皮质动力学是如何在基线时协调并在疾病中受到干扰的理想工具，因为许多 机制在本质上可能是突触的，这两种方法都可以在突触时间尺度上工作。我们是一个团队 神经学家和机械工程师，我们的目标是开发一种系统，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大鼠的大脑。这个 我们方法的基础是一个三维打印(3D打印)的大鼠背侧头骨的替代物--一个“界面” 我们已经成功地将其连接到两只存活良好的大鼠身上。与天然头骨不同的是， 接口板是定制设计和制造的，因此可以适用于引导和固定许多设备 这只动物使用了一种新的手术方法，包括手术前组装。我们的目标是优化我们的设计，以 接口板使两项实验成为可能，这两项实验将对持续威胁相关研究具有新颖性和关键意义 新皮质动力学中的扰动。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个电极广泛分布于整个背侧新皮质。这将使有史以来第一次绘制电子地图 整个背侧新皮质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、行为和大脑状态的转变。我们会 此外，在浅层和深层都放置电极，以收集有关这些层的相对作用的数据 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支持记录 在大脑皮层，同时记录和光遗传刺激区域发挥关键作用 协调新皮质，包括背侧海马、丘脑内侧背侧核(MDN)和 丘脑网状核(TRN)。在这个目标中，8个(以及后来的32个)电极将被植入大脑皮层，用于 记录在背侧海马CA1、MDN和TRN，我们将植入硅探针进行记录 通道和耦合光纤。这将有助于实验检查和测试非 新皮质结构在协调大脑皮质在持续威胁条件下的作用。这些实验 启用此处将提供有关健康和疾病中的新大脑皮层的基本新数据。这项工作将 还将创建一个可定制且灵活的新工具，我们将公开提供该工具以实现 神经科学界的任何人都可以自由地进行动物行为的复杂实验。

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.