Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, United States.
Department of Biology, Emory University, Atlanta, Georgia, United States.
J Neurophysiol. 2023 Mar 1;129(3):651-661. doi: 10.1152/jn.00262.2022. Epub 2023 Feb 8.
Executing complex behaviors requires precise control of muscle activity. Our understanding of how the nervous system learns and controls motor skills relies on recording electromyographic (EMG) signals from multiple muscles that are engaged in the motor task. Despite recent advances in tools for monitoring and manipulating neural activity, methods for recording in situ spiking activity in muscle fibers have changed little in recent decades. Here, we introduce a novel experimental approach to recording high-resolution EMG signals using parylene-coated carbon nanotube fibers (CNTFs). These fibers are fabricated via a wet spinning process and twisted together to create a bipolar electrode. Single CNTFs are strong, extremely flexible, small in diameter (14-24 µm), and have low interface impedance. We present two designs to build bipolar electrode arrays that, due to the small size of CNTF, lead to high spatial resolution EMG recordings. To test the EMG arrays, we recorded the activity of small (4 mm length) vocal muscles in songbirds in an acute setting. CNTF arrays were more flexible and yielded multiunit/bulk EMG recordings with higher SNR compared with stainless steel wire electrodes. Furthermore, we were able to record single-unit recordings not previously reported in these small muscles. CNTF electrodes are therefore well-suited for high-resolution EMG recording in acute settings, and we present both opportunities and challenges for their application in long-term chronic recordings. We introduce a novel approach to record high-resolution EMG signals in small muscles using extremely strong and flexible carbon nanotube fibers (CNTFs). We test their functionality in songbird vocal muscles. Acute EMG recordings successfully yielded multiunit recordings with high SNR. Furthermore, they successfully isolated single-unit spike trains from CNTF recordings. CNTF electrodes have great potential for chronic EMG studies of small, deep muscles that demand high electrode flexibility and strength.
执行复杂行为需要精确控制肌肉活动。我们对神经系统如何学习和控制运动技能的理解依赖于记录参与运动任务的多个肌肉的肌电图（EMG）信号。尽管近年来用于监测和操纵神经活动的工具取得了进展，但近几十年来，记录肌肉纤维中尖峰活动的方法变化不大。在这里，我们介绍了一种使用聚对二甲苯涂层碳纳米管纤维（CNTFs）记录高分辨率 EMG 信号的新实验方法。这些纤维是通过湿法纺丝工艺制造的，并绞合在一起形成双极电极。单 CNTF 强度高、极其灵活、直径小（14-24 µm）且界面阻抗低。我们提出了两种设计方案来构建双极电极阵列，由于 CNTF 的尺寸小，导致 EMG 记录具有高空间分辨率。为了测试 EMG 阵列，我们在急性环境中记录了鸣禽中较小（4 毫米长）的发声肌肉的活动。与不锈钢丝电极相比，CNTF 阵列更灵活，产生的多单位/批量 EMG 记录具有更高的 SNR。此外，我们能够记录以前在这些小肌肉中未报告的单个单位记录。因此，CNTF 电极非常适合在急性环境下进行高分辨率 EMG 记录，并且我们为它们在长期慢性记录中的应用提出了机遇和挑战。我们介绍了一种使用极其强韧和灵活的碳纳米管纤维（CNTFs）记录小肌肉高分辨率 EMG 信号的新方法。我们在鸣禽发声肌肉中测试了它们的功能。急性 EMG 记录成功地产生了具有高 SNR 的多单位记录。此外，它们还成功地从 CNTF 记录中分离出了单个单位的尖峰序列。CNTF 电极非常适合需要高电极灵活性和强度的小型、深层肌肉的慢性 EMG 研究。
