Typical somatomotor physiology of the hand is preserved in a patient with an amputated arm

Electrophysiological signals in the human motor system may change in different ways after deafferentation, with some studies emphasizing reorganization while others propose retained physiology. Understanding whether motor electrophysiology is retained over longer periods of time can be invaluable for patients with paralysis (e.g. ALS or brainstem stroke) when signals from sensorimotor areas may be used for communication or control over neural prosthetic devices. In addition, a maintained electrophysiology can potentially benefit the treatment of phantom limb pains through prolonged use of these signals in a brain-machine interface (BCI). Here, we were presented with the unique opportunity to investigate the physiology of the sensorimotor cortex in a patient with an amputated arm using electrocorticographic (ECoG) measurements. While implanted with an ECoG grid for clinical evaluation of electrical stimulation for phantom limb pain, the patient performed attempted finger movements with the contralateral (lost) hand and executed finger movements with the ipsilateral (healthy) hand. The electrophysiology of the sensorimotor cortex contralateral to the amputated hand remained very similar to that of hand movement in healthy people, with a spatially focused increase of high-frequency band (65-175Hz; HFB) power over the hand region and a distributed decrease in low-frequency band (15-28Hz; LFB) power. The representation of the three different fingers (thumb, index and little) remained intact and HFB patterns could be decoded using support vector learning at single-trial classification accuracies of >90%, based on the first 1-3s of the HFB response. These results demonstrate that hand representations are largely retained in the motor cortex. The intact physiological response of the amputated hand, the high distinguishability of the fingers and fast temporal peak are encouraging for neural prosthetic devices that target the sensorimotor cortex.

人类运动系统中的电生理信号可能会在脱efterentation后以不同的方式发生变化，一些研究强调重组，而另一些研究则提出了保留的生理学。当可能使用来自感觉运动区域的信号用于对神经假体设备的通信或控制时，了解较长时间内运动电生理学是否保留在更长的时间内（例如ALS或脑干中风）是无价的。此外，维持的电生理学可以通过长时间在脑机界面（BCI）中长期使用这些信号来使幻影肢体疼痛的治疗受益。在这里，我们获得了使用电视学（ECOG）测量值截肢臂的患者中感觉运动皮层生理的独特机会。虽然植入了ECOG网格，用于临床评估幻影肢体疼痛的电刺激，但患者用对侧（丢失）手（丢失）手指进行了手指运动，并用同侧（健康）手进行了手指运动。截肢手的感觉运动皮层的电生理学与健康人的手移动的对比非常相似，在空间上，高频带（65-175Hz; HFB）在空间上增加了对手部区域的功率，并且在低频频段（15-28hz）的功率下，具有分布的降低。根据HFB响应的前1-3s，可以使用支撑矢量学习精度以> 90％的单次分类精度来解码三种不同的手指（拇指，指数和小）保持完整的表示。这些结果表明，手动表示主要保留在运动皮层中。截肢手的完整生理反应，手指的高区分性和快速的时间峰对于针对感官皮层的神经假体装置令人鼓舞。