BRAIN EAGER: A Nanophotonic Platform for Multisite Optical Activation in the Brain

有人提出了一种技术，它可以提供一条通往系统神经科学圣杯的道路--获得对神经电路动力学的一定程度的理解。这项技术基于纳米光子学--纳米大小的光学元件，可以大规模集成到小芯片中，然后可以植入动物的大脑。这一平台将使光能够传输到大脑中数千个不同的位置，并能够刺激具有任意动态模式的神经元。这一提出的方法有望为当今科学面临的最大挑战之一--理解大脑如何工作--提供一个关键的垫脚石。它不仅将使一类新的实验能够促进基本的生物学知识，而且最终可能有助于理解神经和神经精神疾病。光刺激和抑制神经活动是阐明神经电路结构和功能的一项强大技术，然而在大多数活体光遗传学实验中，光通过一根光纤传递到大脑中，限制了对大片固定大脑体积的照明。提出了一种新型的纳米光子平台，允许通过单个波导进行大规模并行、多点刺激。纳米光子学的最新进展使所提出的光学探测平台能够将输入光路由到任意激发光点。建议的平台设计为与用于电生理记录的标准硅探针兼容。所提出的平台基于纳米波导由直径约0.5微米的氮化硅(SiN)线嵌入在二氧化硅中，就像纤维一样，对从紫外线到中红外的各种波长的光都是透明的，并且可以是厘米长。然而，与光纤相比，它们要小得多，能够从纳米波导发射光，在任意位置形成多个光束。第一代探头将被制造、测试，然后与最先进的电子探头集成，用于神经验证。然后，这个集成的设备将被用于小鼠皮质，以证明波导为ChR2激活和跨皮质选择性激活提供足够的光的能力。

A technology that could provide a path towards the holy grail of systems neuroscience - gain a level of understanding about the dynamics of neural circuits - is proposed. The technology is based on nano photonics - optical elements that are nanometer in size and can be massively integrated into small chips that could then be inserted into the animal brain. This platform would enable light to be delivered to thousands of different locations in the brain and would enable stimulation of neurons with arbitrary dynamical patterns. This proposed approach is expected to provide a critical stepping stone towards one of the greatest challenges facing science today - the understanding how the brain works. It will not only enable a new class of experiments to advance basic biological knowledge but could eventually contribute to an understanding of neurological and neuropsychiatric diseases. Optical stimulation and silencing of neural activity is a powerful technique for elucidating the structure and function of neural circuitry, however in most in vivo optogenetic experiments, light is delivered into the brain through a single optical fiber limiting illumination to a large, fixed volume of the brain. A novel nanophotonic platform is proposed to allow massively parallel, multi-site stimulation through a single waveguide. Recent advances in nanophotonics enable the proposed optical probe platform which routes input light to an arbitrary excitation spot. The proposed platform is designed to be compatible with standard silicon probes for electrophysiological recordings. The proposed platform is based on nanowaveguides that consist of Silicon Nitride (SiN) wires with ~0.5 micrometers in diameter embedded in SiO2, that just like fibers, are transparent to light of wavelengths from the UV down to the mid-IR, and can be centimeters long. When compared to fibers, however, they are much smaller and enable light to be emitted from the nano-waveguides forming multiple beams at arbitrary locations. A first-generation probe will be fabricated, tested and then integrated with a state of art electrical probe for neural validation. This integrated device will then be used in mouse cortex to demonstrate the ability of waveguides to provide sufficient light for ChR2 activation and selective activation across cortical layers.