CAREER: Uncovering the Impact of Traditional and Novel Chronic Stimulation Modalities on Neural Excitability and Native Neuronal Network Function

长期以来，人们一直希望能够选择性地刺激一小群神经元，用于基础神经科学研究和临床应用。为了满足这一需求，研究人员开发了一种无线技术，可以通过电或光刺激精确地刺激不同的神经元群。因为兴奋性和抑制性神经活动之间的平衡对大脑的感知很重要，一个关键的问题是刺激如何影响这种平衡。兴奋性和抑制性神经元活动之间的不平衡可导致认知功能障碍，是自闭症谱系障碍的标志。此外，创伤性脑损伤、中风和微电极植入等脑损伤也被证明会破坏这种平衡。因此，本CAREER项目的研究目标是建立不同类型的刺激及其对神经元群兴奋性的影响之间的关系。该项目的教育目标是培养具有解决慢性神经接口挑战所需的多学科技能的下一波研究人员。这将通过以下方式实现：1)将本研究中的例子整合到一个面向少数族裔学生的推广计划中，该计划侧重于介绍科学方法和工程设计控制和标准的基本原则，并展示科学和工程如何在神经接口上融合；2)通过建立虚拟的“生物和神经电子接口教育社区”（eBioNIC.org），使神经接口知识更广泛地获得，该社区将成为提供视频和其他培训材料的焦点；3)为整合神经生物学和神经工程学的实践教育提供早期平台。研究者的长期职业愿景是无缝整合大脑和技术，以便为研究长期存在的神经生物学问题（如如何修复脑损伤和神经退行性疾病）提供新的方法。为了实现这一愿景，这个CAREER项目的具体目标是通过工程无线轴突来突破传统的神经刺激限制，利用特定的生物分子来调节大脑中一小部分神经元的活动，然后应用这项技术来调节兴奋-抑制性神经元的不平衡。该项目将采用新的光学技术来解决刺激技术与大脑兴奋-抑制平衡变化之间关系的长期问题。这将通过光学和转基因方法来确定兴奋性和抑制性神经元活动的细胞类型特异性，这是一个重要的参数，可以增强我们对激活大脑区域的生理理解。该项目的指导假设是，不同的刺激方式会不同地改变时空兴奋性和抑制性神经元的活动，从而改变附近不同容量神经元的长期兴奋性。研究计划有两个目标。第一个目标是进一步设计这种无线刺激技术，以可靠和重复地释放特定的生物分子，包括神经递质。涂层技术将应用于无线轴突，利用内源性生物分子在刺激和充电过程中释放生物分子。第二个目标是研究电、光、无线轴突和无线神经化学方式的刺激如何使用体内双光子显微镜和基因编码荧光指示器影响长期兴奋性和抑制性神经元兴奋性。从清醒的头部固定的小鼠中收集体内图像，每天增加间隔，持续两周，然后每周一次，直到12周。电刺激前、电刺激中、电刺激后的数量、距离、时间和神经元亚型密度将随时间变化而变化。该方法能够在电极附近以高空间分辨率跟踪刺激引起的动态变化。通过超小型自由浮动植入物的慢性选择性神经刺激工具的工程设计，研究成果预计将对神经接口的未来设计产生重大影响，这将为科学家提供一种新的工具，用于询问神经网络并在脑机接口中产生不同的感觉，并通过可视化电，光，无线，无线神经化学模式影响长期兴奋性和抑制性神经兴奋性。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。

The ability to selectively stimulate a small group of neurons has been long desired for basic neuroscience studies as well as for clinical applications. To address this need, the investigator has developed a wireless technology that can precisely stimulate a distinct population of neurons by electrical or light stimulation. Because a balance between excitatory and inhibitory neural activity is important for perception in the brain, a key question is how stimulation impacts this balance. An imbalance between excitatory and inhibitory neuronal activity can lead to cognitive dysfunctions and is a hallmark of autism spectrum disorder. Moreover, brain injuries such as traumatic brain injuries, stroke, and microelectrode implantation have also been shown to disrupt this balance. Therefore, the research goal of this CAREER project is to establish the relationship between different types of stimulation and their impact on excitability of neuronal populations. The project's educational goal is to train the next wave of investigators with the multidisciplinary skills needed to solve the chronic neural interface challenge. This will be achieved through: 1) integrating examples from this research into an outreach program to Underrepresented Minority Students that focuses on introducing the fundamental principles of the scientific method and engineering design controls and criteria and on demonstrating how science and engineering converge at the neural interface; 2) making neural interface knowledge more widely accessible by the formation of the virtual "Education in Biological and Neuroelectronic Interface Community" (eBioNIC.org) that will be a focal point for providing videos and other training materials; and 3) providing an early platform for hands-on education on integrating Neurobiology and Neural Engineering.The Investigator's long-term career vision is to seamlessly integrate the brain and technology in order to enable new approaches to studying long-standing neurobiology questions such as how to repair brain injuries and neurodegenerative diseases. Towards this vision, this CAREER project’s specific goals are to break through traditional limitations of neurostimulation by engineering wireless axons that use specific biomolecules to modulate the activity of a small population of neurons in the brain, and then apply this technology to modulate excitatory-inhibitory neuronal imbalances. The project will employ new optical technologies to solve long-standing questions on the relationship between stimulation technologies and changes to the brain’s excitatory-inhibitory balance. This will be achieved using optical and transgenic methods to determine the cell-type specificity of excitatory and inhibitory neuronal activity, an important parameter that can enhance our physiological understanding of the activated brain region. The project's guiding hypothesis is that different stimulation modalities will differentially alter spatio-temporal excitatory and inhibitory neuronal activity, which will in turn alter the long-term excitability of nearby neurons in different capacities. The Research Plan is organized under two objectives. THE FIRST Objective is to further engineer this wireless stimulation technology to reliably and repeatably release specific biomolecules including neurotransmitters. Coating technologies will be applied to the wireless axons to release biomolecules during stimulation and recharge by drawing upon endogenously produced biomolecules. THE SECOND Objective is to investigate how stimulation with electrical, optical, wireless-axon, and wireless neurochemical modalities impacts long-term excitatory and inhibitory neuronal excitability using in vivo 2-photon microscopy and genetically encoded fluorescent indicators. In vivo images will be collected from awake head-fixed mice at increasing intervals daily for two weeks and then once a week until 12 weeks. The number, distance, timing and neuronal subtype densities before, during and after electrical stimulation will be examined over time. The method enables tracking of stimulation-induced dynamic changes with high spatial resolution near the electrodes. Research outcomes are expected to have a significant impact on the future design of neural interfaces through the engineering of chronic selective neural stimulation tools with ultra-small free-floating implants that will provide scientists with a new tool for interrogating neuronal networks and creating different sensations in BCIs and through visualization of how stimulation with electrical, optical, wireless, and wireless neurochemical modalities impacts long-term excitatory and inhibitory neural excitability.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.