ECCS: TOWARDS FREE-FLOATING DISTRIBUTED NEURAL INTERFACES

提案标题：提案目标：提案的目标是设计一个无线框架，可以同时记录整个大脑区域的大规模神经元集合。无线框架将基于自由浮动分布式植入物阵列和外部功率发射器以及重叠六边形平面螺旋线圈（hex-PSC）的阵列。所提出的方法不同于传统的范例，因为大量的微小植入物（直径1 mm，厚度0.1 mm）将分布在目标脑表面上，每个记录1至4根细微丝的单单位活动（SUA（35 μ m四极管，包括特氟隆涂层），同时直接供电，并从可佩戴的头帽询问。在美国，每年约有262，000人患有脊髓损伤，超过800，000人中风。患有严重神经系统疾病的人会完全瘫痪，并依赖护理人员。因为他们大脑发出的指令无法通过自然的交流途径（神经）到达目标肢体。如果一个工程系统能够安全、可靠、有足够的能力从脑电信号中识别出他们的意图，并将其转化为与他人的通信或控制他们瘫痪的肢体或人工假肢，如机器人手臂，那么这将改变这些人的生活。大脑结构极其复杂，理解、记忆、行动和情绪的机制以及许多大脑疾病仍然是神秘的，因为它们是由大脑中广泛网络中大量神经元之间的相互作用产生的。因此，为了更好地了解大脑，神经科学家需要能够记录大脑许多不同区域单个神经元活动的先进工具，正如最近的BRAIN倡议所强调的那样。记录脑电信号的传统方法依赖于单个集中的高密度电极阵列，尽管有上述广域和分布式网络覆盖的要求。现有工作中的另一个问题是由于大的植入物尺寸和布线而导致的组织损伤，导致信号质量随时间推移而劣化。如果植入物很小并且在大脑表面自由浮动，则可以补救。我们建议开发一个分布式系统的小型无线神经接口记录的多通道信号在一个大的大脑区域。分布式植入物将足够小，可以漂浮在大脑表面，而无需连接到任何其他大型集中式结构。我们会找到方法给这些小的植入物输送能量，并与它们交流。我们还将在人脑模型和麻醉动物上进行测试。技术摘要：拟议的工作是试图设计一个无线框架，可以同时记录整个大脑区域的大规模神经元合奏。它将基于自由浮动分布式植入物阵列和重叠线圈的外部发射器/换能器阵列。越来越多的人认识到，大脑中的神经功能来自一个大型的分布式网络。因此，未来的神经记录和调制将需要能够同时与分布在大面积上的多个神经部位进行交互。目前的神经接口显然无法实现这一目标，因为它们的覆盖范围有限。该方法不同于传统的方法，将大量的图钉状微小植入物分布在目标脑表面，每个植入物通过细的微导线记录单个单元活动，同时通过可穿戴的头帽直接供电和询问。通过减少异物反应，小型自由浮动植入物有望最大限度地减少组织损伤并实现慢性无线记录。我们将研究组织反应，如大鼠的炎症和细胞死亡，以评估拟议的自由浮动植入物的寿命，可靠性和保真度。我们将开发具有气密密封的新型封装结构，这需要用于亚毫米尺寸、无线供电、自由浮动器件的新工艺流程。与以前的无线电力传输系统不同，这些系统已经被优化用于为单个植入物供电，所提出的工作中的优化范式将考虑整个大脑区域。我们将优化具有任意方向和对齐的多个植入物的供电。这将通过一种新型的120 °偏移平面线圈外部阵列来实现，该阵列具有全新的驱动机制，在无线电力传输方面提供了前所未有的灵活性。

Proposal Title: Towards Free-Floating Distributed Neural InterfacesProposal Goal: The Proposal objectives are to design a wireless framework that can simultaneously record large scale neuronal ensembles over the entire brain area. The wireless framework will be based on an array of free-floating distributed implants and an external power transmitterand interrogator array of overlapping hexagonal planar spiral coils (hex-PSC). The proposed approach is different from the traditional paradigm in that a vast number of tiny implants (1 mm in diameter and 0.1 mm thick) in the form of pushpins will be distributed over the target brain surface, each recording single unit activities (SUA) from one to four thin microwires (35 um tetrodes including Teflon coating), while being directly powered and interrogated from a wearable head-cap.Nontechnical Abstract:In the United States, approximately 262,000 people suffer from spinal cord injuries and more than 800,000 strokes happen every year. People with severe neurological disorders become completely paralyzed and dependent on caregivers. Because the commands from their brain fail to reach the target limbs in the natural communication pathways (nerves). It would change the lives of these individuals if an engineered system would be safe, secure, and capable enough to recognize their intentions form brain electrical signals, and translate them to communication with others or control their paralyzed limbs or artificial prostheses, such as robotic arms. Brain structure is extremely complex and the mechanisms of understanding, memory, actions, and emotions as well as many brain disorders remain mysterious because they emerge from interactions among large populations of neurons in widespread networks across the brain. Therefore, to better understand the brain, neuroscientists need advanced tools capable of recording the activity of individual neurons over many different areas of the brain, as emphasized in the recent BRAIN initiative. Traditional methods to record brain electrical signals have relied on a single centralized high density electrode array despite the aforementioned requirements of wide area and distributed network coverage. Another problem in prior work is the tissue damage due to large implant size and wiring, resulting in degradation of the signal quality over time. This can be remedied if the implant is small and free-floating on the brain surface. We propose to develop a distributed system of small wireless neural interfaces for recording of multi-channel signals over a large brain area. The distributed implants will be small enough to be floating on the brain surface without being wired to any other large centralized structure. We will find ways to deliver power to these small implants and communicate with them. We will also test them on human brain models and anesthetized animals. Technical Abstract:The proposed work is an attempt to design a wireless framework that can simultaneously record large scale neuronal ensembles over the entire brain area. It will be based on an array of free-floating distributed implants and an external transmitter/interrogator array of overlapping coils. There is increasing realization that neural function in the brain arises from a large distributed network. Thus, neural recording and modulation of the future will require the ability to simultaneously interface with multiple neural sites distributed over a large area. The current neural interfaces clearly fall short of achieving this goal because of their limited area coverage. The proposed approach is different from the traditional paradigm in that a vast number of tiny implants in the form of pushpins will be distributed over the target brain surface, each recording single unit activities from thin microwires, while being directly powered and interrogated from a wearable head-cap.By reducing foreign body reaction, the small free-floating implants are expected to minimize tissue damage and enable chronic wireless recording. We will investigate the tissue response, such as inflammation and cell death in rats to assess the longevity, reliability, and fidelity of the proposed free-floating implants. We will develop novel packaging structures with hermetic sealing, which require new process flows for sub-mm sized, wirelessly-powered, free-floating devices. Unlike previous wireless power transfer systems, which have been optimized for powering a single implant, the optimization paradigm in the proposed work will consider the entire brain area. We will optimize powering of multiple implants with arbitrary orientations and alignments. This will be achieved by a novel 120¢ª offset external array of planar coils with an entirely new drive mechanism, which offers unprecedented flexibility in wireless power delivery.