CAREER: Electro-optic Multiplexing for Massive Scaling of Neural Recording

我们对外部世界的感知、认知和记忆都是通过大脑调节的。目前还不完全清楚大脑中的处理过程是如何产生丰富的经验的。为了了解神经元的活动如何促进大脑中信息的转换，以高分辨率记录大脑不同区域的神经信号是很重要的。一种被广泛使用的记录神经元活动的工具是一种针状的可植入装置，称为神经探针，它穿过组织并有多个记录位点来捕捉大脑中不同神经元的活动。考虑到大脑的复杂性，神经探针上的记录通道数量应该增加，这样才能从中枢神经系统捕获更多的信号。然而，这是以扩大可植入探针为代价的，对脑组织造成严重损害。在这个项目中，研究人员的目标是打破这种权衡，他们设计了一种全新的超高密度神经探针，但具有非常纤细的外形，以揭示大脑功能的神经基础。这将通过使用光来携带来自大脑的记录信号来实现。这种新颖的可扩展技术为高密度神经记录提供了一种独特的方法，可以彻底改变下一代脑机接口的设计，也可以为减轻癫痫、帕金森病和阿尔茨海默病等脑部疾病提供新的治疗方法。该项目为神经工程跨学科领域的新一代学生提供了一个独特的培训机会，涉及纳米技术，光子学，电子学和神经科学。该综合研究项目的技术目标是通过直接记录大脑中的电生理活动，并利用石墨烯的精致电光特性将其编码成不同的光学波长，设计一种新型的超高密度神经接口平台。然后使用片上硅光子微谐振器将光信号密集地多路复用。该方法将大量增加可同时记录的神经元数量，并将提供前所未有的灵敏度和信号保真度。这项多学科研究建立在一系列技术突破的基础上，以利用(i)石墨烯的特殊电光特性将电生理信号编码到光学信号上；（ii）高质量光子微谐振器的窄带共振，用于对许多记录的神经信号进行片上波长域复用。所提出的方法能够同时记录数千个神经元的电光神经，而不需要任何外源性光学标签。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Our perception of the outside world, cognition, and memory are all mediated through our brain. It is not yet completely known how processing in the brain gives rise to the richness of our experience. To understand how the activity of neurons contributes to the transformation of information in the brain, it is important to record neural signals across different areas of the brain with high resolution. One of the widely used tools to record neuronal activity is a needle-shaped implantable device, called neural probe that penetrates through the tissue and has multiple recording sites to capture the activity of different neurons in the brain. Given the complexity of brain, the number of recording channels on the neural probe should be increased so that more signals can be captured from the central nervous system. However, this comes at the cost of enlarging the implantable probe, causing severe damage to the brain tissue. In this project, the researchers aim to break this trade-off by designing a completely new class of ultrahigh density neural probes but with a very slim form factor to unravel the neural basis of brain function. This will be enabled by using light to carry the recorded signals from the brain. This novel scalable technology offers a unique approach for high-density neural recording that can revolutionize the design of next generation brain-machine interfaces and also new therapeutics for mitigating brain disorders such as epilepsy, Parkinson’s and Alzheimer’s disease. This project provides a unique training opportunity for a new generation of students in the interdisciplinary field of neural engineering at the interface of nanotechnology, photonics, electronics and neuroscience.The technical goal of this integrative research project is to design a novel ultrahigh density neural interface platform by directly recording the electrophysiology activity in the brain and encoding it into different optical wavelengths using the exquisite electro-optic properties of graphene. The optical signals will then be densely multiplexed using on-chip silicon photonic microresonators. This method will massively scale up the number of neurons which can be simultaneously recorded and will provide unprecedented sensitivity and signal fidelity. This multidisciplinary research builds on a host of technological breakthroughs to leverage (i) the exceptional electro-optic properties of graphene for encoding electrophysiology signals onto optical signals and (ii) the narrowband resonance of high-quality photonic microresonators for on-chip wavelength-domain multiplexing of many recorded neural signals. The proposed method enables simultaneous electro-optic neural recording from thousands of neurons without the need for any exogenous optical tags.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.