Development of an integrated array for simultaneous optogenetic stimulation and electrical recording to study cortical circuit function in the non-human primate brain

了解非人类灵长类动物（NHP）大脑皮层神经回路的功能， 最接近人类的模型系统，对于理解正常的皮层功能和电路水平基础至关重要 人类大脑紊乱的症状光遗传学已经成为研究神经回路功能的有力工具， 使用光来干扰经遗传修饰以表达光激活微生物的特定细胞类型的活性， 视蛋白，并评估这种扰动对网络活动和行为的影响。虽然成功 在小鼠中，将光遗传学应用于NHP一直具有挑战性，主要是由于缺乏多功能 集成式探头，可在毫米到厘米的体积范围内进行精确的光传输和电生理学检查， NHP皮质的深度。为了观察大的NHP脑，大体积操作是必不可少的。 可测量的电生理或行为效应。一个跨学科的PI团队建议开发和 测试允许大体积时空模式化光遗传学的体内整合穿透阵列 NHP脑中神经回路的调制和电记录。该项目需要协调 4个团队的努力，包括光子器件和用于光遗传学的µLED开发专家，材料和 生物相容性器械包装、灵长类动物神经生理学和电极阵列设计的先驱， 商业化在目标1中，我们开发了该技术，在目标2中，我们在NHP视觉皮层中进行了体内测试。 我们将首先开发一个4x 4 mm穿透10 x10的光电极阵列，其格式类似于井- 建立了犹他州电气阵列（UEA），每个探头作为波导，允许可见光到达 组织深度>1.5mm。在对探针的柄部直径和尖端角度进行初始优化以最小化 组织损伤，我们将在深层皮质组织中进行体内NHP光遗传学实验的概念验证， 使用整个阵列的大面积照明。在第二阶段，我们将通过µ LED开发光耦合， 它将被集成到一个单一的平台，并在体内进行测试，包括位于每个平台上的µLED， 光学探头第二阶段的完成将提供一个功能性的多光极阵列，用于大批量图案化 光遗传学刺激并行工程工作将通过利用 工程资源已经到位的UEA，并将产生两种类型的集成阵列。的 “交错”阵列由插入通过修改的UEA的背板的光极阵列组成， 通过激光烧蚀形成底板通孔的栅格以容纳光极。对于“混合”阵列， 每个光极柄将涂覆有绝缘层，随后是导电层， 记录，同时防止光衰减和刺激伪影。体内测试将评估记录 两种器械的能力以及随后执行同时光学刺激的能力， 电子记录这项技术将允许前所未有的光遗传学研究毫米到厘米 NHP患者的神经回路功能和功能障碍，以及新一代的治疗干预措施 通过细胞类型特异性光学神经控制假体。

Understanding the function of neural circuits in the cerebral cortex of the non-human primate (NHP), the model system closest to human, is crucial to understanding normal cortical function and the circuit-level basis of human brain disorders. Optogenetics has emerged as a powerful tool for studying neural circuit function, by using light to perturb the activity of specific cell types genetically modified to express light-activated microbial opsins, and assessing the consequences of this perturbation on network activity and behavior. While successful in mice, it has been challenging to apply optogenetics to NHPs, largely due to the lack of multifunction integrated probes for precision light delivery and electrophysiology across mm-to-cm volumes through the depth of the NHP cortex. Large volume manipulations are essential in the large NHP brain in order to observe measurable electrophysiological or behavioral effects. An interdisciplinary team of PIs proposes to develop and test in vivo integrated penetrating arrays that allow for large-volume, spatiotemporally patterned optogenetic modulation and electrical recording of neural circuits in the NHP brain. This project requires the coordinated effort of 4 teams, including experts in photonic devices and µLED development for optogenetics, materials and packaging for biocompatible devices, primate neurophysiology, and pioneers in electrode array design and commercialization. In Aim 1 we develop the technology, and in Aim 2 we test it in vivo in the NHP visual cortex. We will initially develop a 4x4 mm penetrating 10x10 optrode array in a format analogous to the well- established Utah Electrical Array (UEA), with each probe serving as a waveguide allowing visible light to reach tissue depths >1.5mm. Following initial optimization of the probe's shank diameter and tip angle to minimize tissue damage, we will perform proof-of-concept in vivo NHP optogenetic experiments in deep cortical tissue, using broad-area illumination of the entire array. In a second stage, we will develop light coupling via µLEDs, which will be integrated into a single platform and tested in vivo, consisting of a µLED located over each optical probe. Completion of stage 2 will deliver a functional multioptrode array for large-volume patterned optogenetic stimulation. Parallel engineering efforts will add electrical recording capability, by utilizing the engineering resources already in place for the UEA, and will generate two types of integrated arrays. The “interleaved” array consists of an optrode array inserted through the back plane of a modified UEA into which a grid of through-backplane holes is made via laser ablation to accommodate the optrodes. For the “hybrid” array, each optrode shank will be coated with an isolation layer followed by a conductive layer, in order to allow recording while preventing light attenuation and stimulation artifacts. In vivo testing will assess the recording capabilities of both devices and subsequently the ability to perform simultaneous optical stimulation and electrical recordings. This technology will allow for unprecedented optogenetic investigations of mm-to-cm scale neural circuit function and dysfunction in NHPs, and for a new generation of therapeutic interventions via cell type specific optical neural control prosthetics.