School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Kanagawa, Japan; Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.
School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Kanagawa, Japan.
Neuroimage. 2018 Dec;183:597-605. doi: 10.1016/j.neuroimage.2018.08.070. Epub 2018 Aug 30.
Bridging between brain activity and machine control, brain-computer interface (BCI) can be employed to activate distributed neural circuits implicated in a specific aspect of motor control. Using a motor imagery-based BCI paradigm, we previously found a disinhibition within the primary motor cortex contralateral to the imagined movement, as evidenced by event-related desynchronization (ERD) of oscillatory cortical activity. Yet it is unclear whether this BCI approach does selectively facilitate corticomotor representations targeted by the imagery. To address this question, we used brain state-dependent transcranial magnetic stimulation while participants performed kinesthetic motor imagery of wrist movements with their right hand and received online visual feedback of the ERD. Single and paired-pulse magnetic stimulation were given to the left primary motor cortex at a low or high level of ERD to assess intracortical excitability. While intracortical facilitation showed no modulation by ERD, short-latency intracortical inhibition was reduced the higher the ERD. Intracortical disinhibition was only found in the agonist muscle targeted by motor imagery at high ERD level, but not in the antagonist muscle. Single pulse motor-evoked potential was also increased the higher the ERD. However, at high ERD level, this facilitatory effect on overall corticospinal excitability was not selective to the agonist muscle. Analogous results were found in two independent experiments, in which participants either performed kinesthetic motor imagery of wrist extension or flexion. Our results showed that motor imagery-based BCI can selectively disinhibit the corticomotor output to the agonist muscle, enabling effector-specific training in patients with motor paralysis.
在大脑活动与机器控制之间架起桥梁，脑机接口（BCI）可用于激活与运动控制特定方面相关的分布式神经回路。我们先前使用基于运动想象的 BCI 范式，发现想象运动对侧的初级运动皮层内存在抑制性去同步（ERD），这表明皮质振荡活动的去同步。然而，目前尚不清楚这种 BCI 方法是否能选择性地促进想象所针对的皮质运动代表区。为了解决这个问题，我们在参与者用右手进行手腕运动的体感运动想象时，使用脑状态相关的经颅磁刺激，并在线反馈 ERD 的去同步情况。在低或高 ERD 水平时，用单脉冲和双脉冲磁刺激作用于左侧初级运动皮层，以评估皮质内兴奋性。虽然皮质内易化没有受到 ERD 的调节，但短潜伏期皮质内抑制在 ERD 越高时越低。只有在高 ERD 水平时，皮质内去抑制才会出现在运动想象所针对的运动肌中，而不是拮抗肌中。高 ERD 水平时，单脉冲运动诱发电位也会增加。然而，这种对整体皮质脊髓兴奋性的促进作用并非针对运动肌，而是在高 ERD 水平时。在两个独立的实验中也发现了类似的结果，其中参与者分别进行手腕伸展或弯曲的体感运动想象。我们的结果表明，基于运动想象的 BCI 可以选择性地去抑制运动肌的皮质运动输出，从而为运动麻痹患者提供特定于效应器的训练。
