Bi-directional Neural interface for Prosthetic Control

生物电子医学是一个正在发展的领域，它使用电子设备来提供治疗效果。这允许治疗药物难以治疗的疾病，或需要具有高水平空间特异性的治疗。例如，多达三分之一的癫痫患者会发展为难治性癫痫，抗癫痫药物无法充分控制癫痫发作。对于这些人来说，使用电刺激靶向癫痫活动的焦点区域的生物电子药物已被证明可以在发病时减少或终止癫痫发作，并且代表了一种潜在的治疗方法。随着生物电子医学领域的发展，我们对神经系统运作的理解也在不断加深。这种理解的增加使得计算机系统与神经系统的紧密结合成为可能，为基于这些脑机接口（bci）创造新技术提供了一条途径。医疗脑机接口的一个重点是为那些周围神经系统（PNS）受损的人提供假体装置——补充或取代因疾病或损伤而丧失的自然能力的机器。在脊髓损伤或肢体丧失的情况下，脑机接口可以完全恢复该人的身体能力和生活质量。这个博士项目的重点是创建和分析一个PNS-BCI植入手臂，能够完全双向通信。从本质上讲，这种设备将能够检测到大脑发送到肢体的神经信号，并利用这些信号来控制另一个设备，比如假肢；然后，它还可以使用来自设备的传感器数据来依次刺激神经，让用户从手臂上体验到来自自然肢体的感觉。目前的手和手臂假肢设计时只考虑控制，因此缺乏感官反馈，使用者面临的一个主要问题是“体现”假肢，即假肢是他们身体的一部分的感觉。目前使用皮肤水平肌肉活动记录的控制系统也无法提供接近自然肢体的灵活性，假肢仅限于少数预先设定的手部姿势。在这两个问题之间，许多手和手臂假肢的使用者最终放弃了他们的使用，其中大多数人对假肢的功能感到沮丧，这是放弃它的原因。如前所述，如果假肢可以通过脑机接口完全融入神经系统，这些问题就可以得到解决，从而使截肢者的生活质量得到提高。本课题的研究问题是：1.；电刺激能产生触觉和本体感觉吗？能否通过解码运动神经元的活动来分类用户想要执行的动作？非侵入性电极（如袖带电极）能否选择性地刺激神经内的特定神经束？不同的刺激参数如何影响植入电极的神经的急性行为和慢性健康？这些研究问题将通过结合模拟、体外和体内测试来回答，以量化不同设备设计和操作参数的行为。迄今为止，没有研究或可用的设备在脑机接口中提供完整的双向通信；实现这一目标将代表着肢体丧失者朝着完全功能恢复迈出的重要一步。该研究项目与EPRSC在辅助技术、生物信息学和临床技术方面的研究兴趣密切相关。

Bioelectronic medicine is a growing field that uses electrical devices to provide therapeutic effects. This allows for the treatment of conditions that can be intractable to drugs, or require a therapy with a high level of spatial specificity. For example, up to a third of people with epilepsy will develop refractory epilepsy, where anti-epileptic drugs don't work to sufficiently control seizures. For these people, bioelectronic medicines that use electrical stimulation targeted to the focal region of the epileptic activity have been shown to reduce or terminate seizures at onset, and represent a potential treatment for their condition. As the field of bioelectronic medicine has developed, so has our understanding of the workings of the nervous system. This increase in understanding has made it possible to closely integrate computer systems with the nervous system, providing a path to creating new technologies based on these brain-computer interfaces (BCIs). A key focus for medical BCIs has been in providing prosthetic devices - machines that supplement or replace natural capabilities lost to disease or injury - for those with damage to the peripheral nervous system (PNS). In cases such as spinal cord injury or loss of a limb, a BCI could allow for the complete restoration of that person's physical capacity and quality of life.This PhD project is focussed on creating and analysing a PNS-BCI to be implanted into the arm, capable of full bi-directional communication. In essence, such a device would be able to detect nervous signals sent to the limb by the brain and use those to control another device, such as a prosthetic arm; it could then also use sensor data from the device to stimulate the nerves in turn, allowing the user to experience from the arm the sensations that would come from a natural limb. A major issue faced by users of current hand and arm prosthetics, which are designed only with control in mind and so lack sensory feedback, is "embodying" the artificial limb - the sense of the limb being a part of their body. Current control systems that use skin-level muscle activity recordings are also unable to provide dexterity close to a natural limb, with prosthetics limited to a small number of pre-set hand postures. Between these two problems, many users of hand and arm prosthetics end up desisting in their use, with most citing frustration with the capabilities of the prosthetic as a reason for abandoning it. If the prosthetic could be fully integrated into the nervous system through a BCI, as outlined above, these issues could be solved to allow for a much greater quality of life for amputees.The research questions for this project are:1. Can electrical stimulation produce the sensations of touch and proprioception?2. Can the activity of the motor neurones be decoded to classify what action the user wants to perform?3. Can a non-invasive electrode, such as a cuff electrode, selectively stimulate specific fascicles within the nerve?4. How do different stimulation parameters affect both the acute behaviour and chronic health of nerves implanted with electrodes?These research questions will be answered by using a combination of simulations, ex vivo and in vivo tests to quantify the behaviour of different device designs and operational parameters. No research or available device to date provides full bi-directional communication in a BCI; achieving this would represent a significant step towards fully functional restoration for people with limb loss. This research project aligns strongly with the EPRSC's research interests in Assistive Technology, Biological Informatics and Clinical Technologies.