ECCS: TOWARDS FREE-FLOATING DISTRIBUTED NEURAL INTERFACES

提案题目：迈向自由浮动分布式神经接口提案目标：提案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。无线框架将基于一组自由浮动的分布式植入物和一个由重叠的六边形平面螺旋线圈（hexx - psc）组成的外部功率发射器和询问器阵列。所提出的方法与传统的方法不同，因为大量的微型植入物（直径1毫米，厚0.1毫米）将以图钉的形式分布在目标大脑表面，每个植入物记录单个单元活动（SUA），从一到四根细微线（35微米的四极管，包括聚四氟乙烯涂层），同时直接从可穿戴的头帽供电和审讯。摘要：在美国，大约有26.2万人患有脊髓损伤，每年有超过80万人中风。患有严重神经系统疾病的人会完全瘫痪，并依赖照顾者。因为来自大脑的指令不能通过自然的交流途径（神经）到达目标肢体。如果一个工程系统安全可靠，并且有足够的能力从大脑电信号中识别出他们的意图，并将其转化为与他人的交流，或控制他们瘫痪的肢体或人工假肢，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、行动和情感以及许多脑部疾病的机制仍然是神秘的，因为它们是由大脑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，神经科学家需要先进的工具，能够记录大脑许多不同区域的单个神经元的活动，正如最近的brain计划所强调的那样。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。先前工作中的另一个问题是由于较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下降。如果植入物很小并且在大脑表面自由漂浮，这就可以得到补救。我们建议开发一种小型无线神经接口的分布式系统，用于在大的大脑区域记录多通道信号。这种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。我们将找到给这些小植入体供电并与它们通信的方法。我们还将在人脑模型和麻醉动物身上进行测试。技术摘要：提出的工作是尝试设计一个无线框架，可以同时记录整个大脑区域的大规模神经元集合。它将基于一组自由浮动的分布式植入物和一个由重叠线圈组成的外部发射器/询问器阵列。越来越多的人认识到，大脑中的神经功能源于一个庞大的分布式网络。因此，未来的神经记录和调制将需要同时与分布在大面积上的多个神经位点进行交互的能力。目前的神经接口显然无法实现这一目标，因为它们覆盖的区域有限。所提出的方法与传统的范例不同，因为大量的图钉形式的微型植入物将分布在目标大脑表面，每个植入物通过细微细线记录单个单元的活动，同时由可穿戴的头帽直接供电和询问。通过减少异物反应，这种小型自由漂浮的植入物有望将组织损伤降到最低，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，这需要新的工艺流程，用于亚毫米尺寸，无线供电，自由浮动的设备。不像以前的无线电力传输系统，已经优化为单个植入物供电，在提出的工作中的优化范例将考虑整个大脑区域。我们将以任意的方向和排列优化多个植入体的供电。这将通过一种新颖的120°°偏移平面线圈外部阵列实现，该阵列具有全新的驱动机构，为无线电力输送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.