对运动神经元的突触输入是基础肌肉协作激活功能不同任务有不同的光谱特征
Daniele Borzelli1,2, Taian M M Vieira3,4, Alberto Botter3,4
1Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Messina, Italy.
Journal of neurophysiology
|April 17, 2024
概括
中枢神经系统使用不同的神经通路来产生四肢力量,而不是调节关节硬. 刚性控制涉及特定的运动神经元输入,具有更高的同步性和皮质起源,与产生力不同.
科学领域:
- 神经科学是一个神经科学.
- 发动机控制器的控制器
- 生物物理学的生物物理.
背景情况:
- 中枢神经系统 (CNS) 可以通过使用各种肌肉激活模式来实现类似的运动结果.
- 敌对肌肉的协同收缩,虽然不能直接产生扭矩,但在调节关节机械度方面起着至关重要的作用.
- 现有的理论提出了单独的神经通路的力量生成和刚性调制,但突触输入差异仍然没有特征.
研究的目的:
- 为了研究和区分运动神经元 (MN) 的突触输入,在联合收缩期间进行硬度调制与力产生.
- 为了确定运动神经元激活模式的不同神经来源和特征,为这两个功能任务.
主要方法:
- 参与者执行上肢共收缩任务 (双臂和三臂) 进行硬度调节或产生力.
- 通过高密度电肌图 (EMG) 信号的分解识别了运动神经元尖峰列车.
- 交叉肌肉图和连贯性分析 (交叉肌肉和肌肉内) 用于检查MN同步和突触输入特征.
主要成果:
- 在调节度时,与产生力相比,在MNs之间观察到更高的同步.
- 交叉肌肉连贯性分析显示,在刚性调节过程中,β频段峰值 (暗示皮质起源),在力生成过程中缺席.
- 肌肉内连贯性分析确定了不同的MN子集,这些MN专门用于产生力或调节硬度.
结论:
- 这些发现表明,硬度调节的分离皮层输入和途径与控制力生成的不同.
- 硬度调节似乎是由特定的皮质输入驱动的,这些输入针对单独的一组运动神经元.
- 这项研究为肌肉招募的神经策略提供了新的见解,突出了不同运动任务的突触输入的特定光谱特征.
更多相关视频
相关概念视频
Motor Unit Stimulation
1.5K
When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
1.5K
Muscle Stimulation Frequency
2.2K
The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
2.2K
Motor Units
3.9K
The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
Motor units come in different sizes, with smaller units...
Motor units come in different sizes, with smaller units...
3.9K
Excitation-Contraction Coupling in Skeletal Muscles
8.2K
Excitation-contraction coupling is a series of events that occur between generating an action potential and initiating a muscle contraction. It occurs at the triad, a structure found in skeletal muscle fibers that comprise a T-tubule and terminal cisternae of the sarcoplasmic reticulum on each side. These triads are visible in longitudinally sectioned muscle fibers. They are typically located at the A-I junction — the junction between the A and I bands of the sarcomere.
When an action...
When an action...
8.2K
The Neuromuscular Junction
9.6K
The nervous system consists of complex motor neuron circuits, including upper motor neurons originating from the cerebral cortex and lower motor neurons starting in the spinal cord, coordinating both voluntary and involuntary movements. Among these, somatic motor neurons activate skeletal muscles and are classified into alpha, beta, and gamma types. Alpha neurons are vital for voluntary movement coordination, while gamma neurons adjust muscle spindle sensitivity, and the function of beta...
9.6K
Muscle Contraction
6.4K
In skeletal muscles, acetylcholine is released by nerve terminals at the motor endplate—the point of synaptic communication between motor neurons and muscle fibers. The binding of acetylcholine to its receptors on the sarcolemma allows entry of sodium ions into the cell and triggers an action potential in the muscle cell. Thus, electrical signals from the brain are transmitted to the muscle. Subsequently, the enzyme acetylcholinesterase breaks down acetylcholine to prevent excessive...
6.4K


