ASCENT: Ultra-high Throughput Neural Recording using Flexible, Polymer-based Shanks as Terahertz Dielectric Waveguides

ASCENT：使用柔性聚合物柄作为太赫兹介电波导进行超高吞吐量神经记录

• 批准号: 2133138
• 负责人: Constantine Sideris
• 金额: $ 150万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-15 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2133138&HistoricalAwards=false
• 关键词: ASCENT; Ultra; Throughput; Neural; Recording

Brain Machine Interfaces (BMI) are used to record the electrical signals of the neurons in the brain and gain insights into the complex processes occurring in the brain and nervous system. This understanding is crucial to repair or augment cognitive and/or sensory and motor functions, which might be necessary, e.g., due to damage to the brain sustained by injuries or diseases. Traditional recording by electroencephalography (EEG) or functional magnetic resonance imaging (MRI) is too crude, cumbersome, and slow for many of these tasks; therefore, BMIs with implanted microelectrodes need to be used. However, state of the art implantable electrode arrays (IEAs) made from rigid silicon not only have short lifetimes but can also damage the brain tissue and cause scar formation. Recently, IEAs have been developed using flexible polymer-based shanks which minimize tissue damage during implantation, significantly increasing safety and paving the way towards long-term recording. Unfortunately, the number of electrodes, and thus the amount of data that can be recorded, is very limited. To pave the way for new basic science discoveries in neuroscience and the development of new, safe BMIs to treat individuals with brain injury or disease, this project introduces a new, completely wireless approach that has virtually unlimited data bandwidth for communicating data outside of the brain and enables safe, long term brain recording via biocompatible, flexible polymer electrodes. The system is expected to have a huge impact on advancing the state-of-the-art in IEA technology by enabling, for the first time ever, safe and high-density neural recording over multiple year-long durations. The technological advances in hybrid silicon-polymer fabrication and chip-to-chip communication via polymer waveguides will also hold scientific and practical application value in their own right.A major problem facing brain machine interfaces is achieving both high data throughput and long lifespans when recording neural activity. To overcome current limitations on recording density and lifetime, this project will develop and prototype a new implantable electrode array technology that combines active silicon complementary metal oxide semiconductor (CMOS)-based electrodes with a biocompatible polymer shank. The Parylene C polymer is flexible and can be microfabricated such that multiple custom, fully wireless CMOS neural recording chiplets can be arranged along the length of each shank. The polymer shank, acting as a dielectric waveguide, will carry both red light and Terahertz (THz) radio-frequency energy from outside the brain to the chiplets for power harvesting and backscatter data communication, respectively, obviating the need for wires. On-chip photodiodes will rectify the incident optical light for powering each chip, and on-chip THz antennas will be used to modulate the locally recorded and amplified neuronal data onto the THz carrier signal inside the polymer shank via backscatter communication. Extensive modeling will be done of the electromagnetic characteristics of the polymer shank waveguides at both optical and THz wavelengths in order to optimize the shank cross-section and design of the THz surface coupling antennas for maximizing system efficiency and communication bandwidth. Each chiplet will contain a dense neural recording electrode array with active amplification, filtering, and spike detection circuitry for recording, digitizing, and compressing neuronal data before modulating it on the THz carrier signal and sending it to the base via the polymer shank waveguide. Importantly, this paradigm achieves a completely wireless system that maximizes the number of neural recording sites and contributes a new hybrid silicon-polymer architecture capable of efficient, high-bandwidth quasi-optical chip-to-chip communication.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.

脑机接口 (BMI) 用于记录大脑中神经元的电信号，并深入了解大脑和神经系统中发生的复杂过程。这种理解对于修复或增强认知和/或感觉和运动功能至关重要，这可能是必要的，例如，由于受伤或疾病对大脑造成的损害。对于许多此类任务来说，传统的脑电图 (EEG) 或功能性磁共振成像 (MRI) 记录方式过于粗糙、繁琐且缓慢；因此，需要使用植入微电极的BMI。然而，由刚性硅制成的最先进的植入式电极阵列（IEA）不仅寿命短，而且还会损伤脑组织并导致疤痕形成。最近，IEA 已开发出使用基于柔性聚合物的柄，可最大程度地减少植入过程中的组织损伤，显着提高安全性并为长期记录铺平道路。不幸的是，电极的数量以及因此可以记录的数据量非常有限。为了为神经科学领域的新基础科学发现以及开发新的、安全的脑机接口来治疗脑损伤或疾病的个体铺平道路，该项目引入了一种新的、完全无线的方法，该方法具有几乎无限的数据带宽，用于在大脑外部通信数据并通过生物相容性、柔性聚合物电极实现安全、长期的大脑记录。该系统首次实现长达数年的安全、高密度神经记录，预计将对推进 IEA 技术的最先进水平产生巨大影响。混合硅聚合物制造和通过聚合物波导进行芯片间通信的技术进步本身也将具有科学和实际应用价值。脑机接口面临的一个主要问题是在记录时实现高数据吞吐量和长寿命神经活动。为了克服当前记录密度和寿命的限制，该项目将开发一种新的植入式电极阵列技术并进行原型设计，该技术将基于活性硅互补金属氧化物半导体（CMOS）的电极与生物相容性聚合物柄相结合。 Parylene C 聚合物非常灵活，可以进行微加工，以便可以沿着每个柄的长度排列多个定制的、完全无线的 CMOS 神经记录小芯片。聚合物柄充当介电波导，将红光和太赫兹（THz）射频能量从大脑外部传输到小芯片，分别用于能量收集和反向散射数据通信，从而无需电线。片上光电二极管将整流入射光，为每个芯片供电，片上太赫兹天线将用于通过反向散射通信将本地记录和放大的神经元数据调制到聚合物柄内的太赫兹载波信号上。将对聚合物柄波导在光学和太赫兹波长下的电磁特性进行广泛的建模，以优化太赫兹表面耦合天线的柄横截面和设计，从而最大限度地提高系统效率和通信带宽。每个小芯片将包含一个密集的神经记录电极阵列，具有主动放大、滤波和尖峰检测电路，用于记录、数字化和压缩神经元数据，然后在太赫兹载波信号上进行调制并通过聚合物柄波导将其发送到基座。重要的是，这种范例实现了一个完全无线的系统，最大限度地增加了神经记录站点的数量，并贡献了一种新的混合硅聚合物架构，能够实现高效、高带宽的准光芯片到芯片通信。该奖项反映了 NSF 的法定使命和通过使用基金会的智力价值和更广泛的影响审查标准进行评估，该项目被认为值得支持。