| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4320749 | Neuron | 2015 | 12 Pages |
•A wearable microscope straps to the human body to study neuromuscular physiology•The microscope reveals the contractile dynamics of single motor units•Time courses of sarcomere displacements report muscle force generation dynamics•Post-stroke spasticity patients exhibited abnormal involuntary sarcomere dynamics
SummaryMotor units comprise a pre-synaptic motor neuron and multiple post-synaptic muscle fibers. Many movement disorders disrupt motor unit contractile dynamics and the structure of sarcomeres, skeletal muscle’s contractile units. Despite the motor unit’s centrality to neuromuscular physiology, no extant technology can image sarcomere twitch dynamics in live humans. We created a wearable microscope equipped with a microendoscope for minimally invasive observation of sarcomere lengths and contractile dynamics in any major skeletal muscle. By electrically stimulating twitches via the microendoscope and visualizing the sarcomere displacements, we monitored single motor unit contractions in soleus and vastus lateralis muscles of healthy individuals. Control experiments verified that these evoked twitches involved neuromuscular transmission and faithfully reported muscle force generation. In post-stroke patients with spasticity of the biceps brachii, we found involuntary microscopic contractions and sarcomere length abnormalities. The wearable microscope facilitates exploration of many basic and disease-related neuromuscular phenomena never visualized before in live humans.Video Abstract To view the video inline, enable JavaScript on your browser. However, you can download and view the video by clicking on the icon belowHelp with MP4 filesOptionsDownload video (24898 K)
