ECCS: TOWARDS FREE-FLOATING DISTRIBUTED NEURAL INTERFACES

提案标题：走向自由浮动的分布式神经接口提案目标：提案的目标是设计一种无线框架，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传输器和交叠六角平面螺旋线圈询问器阵列(Hex-PSC)。这种方法不同于传统的模式，大量以图钉形式分布的微小植入物(直径1 mm，厚0.1 mm)将分布在目标脑表面，每个植入物记录从一到四根细微线(包括特氟隆涂层的35um四极管)的单个单位活动(SUA)，同时通过可穿戴式头盔直接供电和审问。非技术摘要：在美国，每年约有26.2万人遭受脊髓损伤，超过80万人中风。患有严重神经障碍的人会变得完全瘫痪，依赖照顾者。因为他们大脑的指令无法到达自然通信路径(神经)中的目标肢体。如果一个工程系统足够安全、可靠，并有足够的能力从大脑电信号中识别他们的意图，并将其转化为与他人交流或控制他们瘫痪的肢体或假肢，如机械臂，这将改变这些人的生活。大脑结构极其复杂，理解、记忆、行为和情绪的机制以及许多大脑疾病仍然是个谜，因为它们出现在大脑广泛网络中的大量神经元之间的相互作用中。因此，为了更好地了解大脑，神经科学家需要先进的工具来记录大脑许多不同区域中单个神经元的活动，正如最近的大脑倡议所强调的那样。传统的记录脑电信号的方法依赖于单一的集中式高密度电极阵列，尽管前面提到的广域和分布式网络覆盖的要求。以前工作中的另一个问题是由于大的植入物尺寸和布线而造成的组织损伤，导致信号质量随着时间的推移而退化。如果植入物很小，并且自由漂浮在大脑表面，这种情况可以得到补救。我们建议开发一个分布式的小型无线神经接口系统，用于在大范围的大脑区域记录多通道信号。分布式植入物将足够小，可以漂浮在大脑表面，而不会连接到任何其他大型集中式结构。我们将找到向这些小型植入物输送电力的方法，并与它们进行交流。我们还将在人脑模型和麻醉动物上测试它们。技术摘要：这项拟议的工作是试图设计一种无线框架，可以同时记录整个大脑区域的大规模神经元集合。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/询问器阵列。越来越多的人意识到，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同时与分布在大范围内的多个神经部位对接的能力。目前的神经接口显然不能实现这一目标，因为它们的覆盖区域有限。这种方法与传统的方法不同，大量以图钉形式分布的微小植入物将分布在目标大脑表面，每个植入物都通过细微线记录单个单位的活动，同时通过可穿戴式头帽直接供电和询问。通过减少异物反应，小型自由漂浮植入物有望将组织损伤降至最低，并实现长期无线记录。我们将调查大鼠的组织反应，如炎症和细胞死亡，以评估拟议的自由漂浮植入物的寿命、可靠性和保真度。我们将开发具有密封的新型封装结构，这需要用于亚毫米尺寸、无线供电、自由浮动设备的新工艺流程。与以前的无线能量传输系统不同，无线能量传输系统已经针对单个植入物进行了优化，拟议工作中的优化范例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动力。这将通过采用全新驱动机制的新型120？偏置平面线圈外部阵列来实现，从而在无线电能传输方面提供前所未有的灵活性。

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.