Neuroplasticity induced by functional electrical stimulation

功能性电刺激诱导的神经可塑性

• 批准号: RGPIN-2014-06076
• 负责人: Masani, Kei
• 金额: $ 1.82万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567577
• 关键词: Neuroplasticity; induced; functional; electrical; stimulation

Compromised standing and walking function among people who have paralyzed muscles due to a neurological disease or injury, such as spinal cord injury or stroke, critically limits their ability to perform activities of daily living, and reduces their quality of life. Functional electrical stimulation, which is a method that can artificially activate muscles in the paralyzed limbs by use of electrical stimulation, can lead to improvement of patient’s affected limb function. For example, when a person with a paralyzed arm needs to grasp a coffee cup, muscles that close fingers are stimulated to produce a grasping movement. This is an effective way to regain functional movements, but it is practically difficult to apply to many complex movements which are required during activities of daily living. It was discovered that repetitive use of functional electrical stimulation can cause permanent changes of the neural circuits in the brain and/or the spinal cord, which is the so-called neuroplasticity. This discovery could have tremendous impacts in neurorehabiliation but the neural mechanisms and the effective ways of using functional electrical stimulation to induce the neuroplasticity are not fully understood. One probable mechanism behind the neuroplasticity induced by functional electrical stimulation is the synaptic strengthening at the spinal cord. When a command from brain and the signal caused by electrical stimulation which is traveling backward on the motor nerve meet at spinal cord, the strength of the synaptic connection between the brain and the muscle increases (i.e., how effectively the command from brain travels to muscle). Repeating this process leads to permanent strengthening of the connection between the brain and the muscle, which can increase the muscle force and improve limb movement. The proposed research program aims to explore the effective ways that functional electrical stimulation can facilitate neuroplasticity in the human motor control system, focusing on this synaptic strengthening at the spinal cord, i.e., what is happening in the spinal cord. For this mechanism, two neural signals are required: One from the brain and the other from peripheral nerves. A signal from the brain can be induced simply by the patient’s voluntary effort (i.e., if patient want to move a limb, a command from brain will travel to the muscle). The other way to cause a signal from the brain is to use transcranial magnetic stimulation. By stimulating the cortical area of the brain responsible for the limb moment, transcranial magnetic stimulation activates the responsible neurons and the neurons send a command to the muscle. There are four ways to cause the neural signal from peripheral nerves; 1) to stimulate the sensory nerve trunk at a nerve pass to the target muscle, 2) to stimulate the nerve ending within the target muscle, 3) to stimulate the motor neurons in the spinal cord, 4) to stimulate the motor nerve trunk at a nerve pass to the target muscle. By appropriately combining the brain neural signal and neural signal from peripheral nerves, it is hypothesized that neuroplasticity can be induced at the spinal cord. In this program, I will test each combination systematically to investigate and develop the most effective way to deliver functional electrical stimulation to induce the synaptic strengthening between the brain and the muscle. At the end, this program will develop a basis of a neuroengineering method which can help people with paralyzed muscles regain their lost movements, which will inevitably lead to increased quality of life.

由于神经系统疾病或损伤（如脊髓损伤或中风）导致肌肉瘫痪的人的站立和行走功能受损，严重限制了他们进行日常生活活动的能力，并降低了他们的生活质量。功能性电刺激是一种通过电刺激人工激活瘫痪肢体肌肉的方法，可以改善患者患肢的功能。例如，当手臂瘫痪的人需要握住咖啡杯时，闭合手指的肌肉会受到刺激，产生抓握运动。这是恢复功能性运动的有效方法，但实际上很难应用于日常生活活动中所需的许多复杂运动。人们发现，重复使用功能性电刺激可以引起大脑和/或脊髓中神经回路的永久性变化，这就是所谓的神经可塑性。这一发现可能对神经康复产生巨大影响，但神经机制和使用功能性电刺激诱导神经可塑性的有效方法尚未完全了解。功能性电刺激诱导的神经可塑性背后的一个可能机制是脊髓的突触强化。当来自大脑的命令和由在运动神经上向后行进的电刺激引起的信号在脊髓处相遇时，大脑和肌肉之间的突触连接的强度增加（即，从大脑到肌肉的命令的有效性）。重复这个过程会导致大脑和肌肉之间的连接永久加强，这可以增加肌肉力量并改善肢体运动。拟议的研究计划旨在探索功能性电刺激促进人类运动控制系统神经可塑性的有效方法，重点是脊髓的突触强化，即，脊髓里发生了什么这种机制需要两种神经信号：一种来自大脑，另一种来自外周神经。来自大脑的信号可以简单地通过患者的自愿努力（即，如果患者想要移动肢体，则来自大脑的命令将传送到肌肉）。另一种从大脑发出信号的方法是使用经颅磁刺激。通过刺激负责肢体运动的大脑皮层区域，经颅磁刺激激活了负责的神经元，神经元向肌肉发送命令。有四种方式引起来自外周神经的神经信号：1）刺激在通向目标肌肉的神经通路处的感觉神经干，2）刺激目标肌肉内的神经末梢，3）刺激脊髓中的运动神经元，4）刺激在通向目标肌肉的神经通路处的运动神经干。通过适当地组合脑神经信号和来自外周神经的神经信号，假设可以在脊髓处诱导神经可塑性。在这个项目中，我将系统地测试每种组合，以研究和开发最有效的方式来提供功能性电刺激，以诱导大脑和肌肉之间的突触加强。最后，该计划将开发一种神经工程方法的基础，可以帮助肌肉瘫痪的人恢复失去的运动，这将不可避免地提高生活质量。