Chen Yi, Wang Yu, Chen Lu, Yang Xinxin, Gemoets Darren E, Carp Jonathan S, Chen Xiang Yang, Wolpaw Jonathan R
National Center for Adaptive Neurotechnologies, Stratton VA Medical Center, Albany NY 12208.
Department of Biomedical Sciences, State University of New York, Albany, NY 12222.
bioRxiv. 2025 Jul 3:2024.12.09.627519. doi: 10.1101/2024.12.09.627519.
Operant conditioning of the spinal stretch reflex or its electrical analog, the H-reflex, induces plasticity in the brain and spinal cord that increases (up-conditioning) or decreases (down-conditioning) the reflex elicited by primary afferent input to the spinal motoneuron. In rats in which the sciatic nerve is transected and repaired, soleus (SOL) H-reflex up-conditioning during regeneration strengthens primary afferent reinnervation of SOL motoneurons and improves recovery of the SOL H-reflex. This suggests that H-reflex up-conditioning could improve functional recovery after nerve injury and repair. To explore this possibility, we examined the impact of SOL H-reflex up- or down-conditioning during sciatic regeneration on recovery of locomotor symmetry. Sprague-Dawley rats were implanted with EMG electrodes in right SOL and a stimulating cuff on right posterior tibial nerve. After control data collection, right sciatic nerve was transected and repaired. Control EMG and H-reflex data collection continued for 20 more days. The rat was then exposed for 100 days to either: continued control data collection; SOL H-reflex up-conditioning; or SOL H-reflex down-conditioning. Locomotor EMG, H-reflex, and kinematics were assessed before nerve transection and 120 days after transection. H-reflex up-conditioning improved H-reflex recovery and also restored right/left step symmetry. H-reflex down-conditioning did not worsen H-reflex recovery or right/left step asymmetry. These results suggest that H-reflex up-conditioning might enhance functional recovery after nerve injury in humans. They also confirm previous results indicating that compensatory plasticity prevents inappropriate H-reflex conditioning (i.e., down-conditioning) from further impairing function.
脊髓牵张反射或其电模拟物H反射的操作性条件反射可在大脑和脊髓中诱导可塑性，从而增加（增强性条件反射）或降低（减弱性条件反射）由初级传入输入至脊髓运动神经元所引发的反射。在坐骨神经被切断并修复的大鼠中，再生过程中比目鱼肌（SOL）H反射的增强性条件反射可加强SOL运动神经元的初级传入再支配，并改善SOL H反射的恢复。这表明H反射增强性条件反射可能会改善神经损伤和修复后的功能恢复。为了探究这种可能性，我们研究了坐骨神经再生过程中SOL H反射增强或减弱性条件反射对运动对称性恢复的影响。将Sprague-Dawley大鼠右侧SOL植入肌电图电极，并在右侧胫后神经上放置刺激袖带。在收集对照数据后，切断并修复右侧坐骨神经。继续收集对照肌电图和H反射数据20天。然后，将大鼠暴露于以下情况100天：继续收集对照数据；SOL H反射增强性条件反射；或SOL H反射减弱性条件反射。在神经切断前和切断后120天评估运动肌电图、H反射和运动学指标。H反射增强性条件反射改善了H反射的恢复，并恢复了左右步幅对称性。H反射减弱性条件反射并未使H反射恢复变差或左右步幅不对称加剧。这些结果表明，H反射增强性条件反射可能会增强人类神经损伤后的功能恢复。它们还证实了先前的结果，即代偿性可塑性可防止不适当的H反射条件反射（即减弱性条件反射）进一步损害功能。
