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

提出了一种技术，可以提供一条通往系统神经科学圣杯的道路-获得对神经回路动力学的一定程度的理解。 该技术基于纳米光子学-纳米尺寸的光学元件，可以大规模集成到小芯片中，然后插入动物大脑。 该平台将使光能够被传递到大脑中数千个不同的位置，并能够以任意的动态模式刺激神经元。这种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--提供关键的垫脚石。它不仅将使一类新的实验能够推进基础生物学知识，而且最终可能有助于理解神经和神经精神疾病。神经活动的光学刺激和沉默是用于阐明神经回路的结构和功能的强大技术，然而在大多数体内光遗传学实验中，光通过单个光纤被递送到大脑中，从而将照明限制到大脑的大的固定体积。 提出了一种新的纳米光子平台，以允许通过单个波导进行大规模并行的多位点刺激。纳米光子学的最新进展使得所提出的光学探针平台能够将输入光路由到任意激发点。所提出的平台被设计为与用于电生理记录的标准硅探针兼容。 所提出的平台基于由直径约为0.5微米的氮化硅（SiN）线嵌入SiO2组成的半导体波导，就像光纤一样，对从UV到中红外的波长的光透明，并且可以是厘米长。然而，与光纤相比，它们要小得多，并且能够从纳米波导发射光，从而在任意位置形成多个光束。 第一代探针将被制造、测试，然后与最先进的电探针集成，用于神经验证。然后将该集成装置用于小鼠皮质，以证明波导为ChR 2激活和跨皮质层的选择性激活提供足够光的能力。

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.