Related Experiment Video
Updated: Jul 10, 2026
13:07
Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo
Published on: December 5, 2012
The output from human inspiratory motoneurone pools
Jane E Butler1, Simon C Gandevia
1Prince of Wales Medical Research Institute and University of New South Wales, Sydney, Australia.
The Journal of Physiology
|November 3, 2007
Summary
Adequate breathing relies on chest muscles and a clear airway. This study reveals distinct neural control patterns and firing frequencies among respiratory muscles, suggesting a neuromechanical principle guiding motor output.
Area of Science:
- Physiology
- Neuroscience
- Respiratory Medicine
Background:
- Pulmonary ventilation is crucial for survival, depending on chest wall muscle contraction and an open upper airway.
- Bulbospinal outputs control respiratory motoneurone pools, generating muscle contractions necessary for breathing.
- Understanding the neural drive to respiratory muscles is vital for diagnosing and treating respiratory disorders.
Purpose of the Study:
- To investigate the differences in motoneuronal output characteristics among various chest wall muscles during breathing.
- To explore the relationship between motoneuronal drive and the mechanical advantage of respiratory muscles.
- To characterize the neural control of the genioglossus muscle for maintaining upper airway patency.
Main Methods:
- Analysis of phasic inspiratory output from single motor units in five chest wall muscles, including the diaphragm.
- Development of a novel time and frequency plot to visualize motoneurone population behavior.
- Recording of motor unit activity in intercostal muscles to assess correlation with mechanical advantage.
Main Results:
- Significant differences observed in the onset, recruitment, and firing frequency of motoneuronal drive across different chest wall muscles.
- Tonic firing with inspiratory modulation is prevalent in external intercostal muscles but uncommon in the diaphragm.
- A linear correlation was found between inspiratory firing magnitude and the mechanical advantage of the intercostal muscle region.
Conclusions:
- The central nervous system (CNS) appears to employ a 'neuromechanical' principle, alongside Henneman's size principle, to control motoneuronal output based on muscle mechanical advantage.
- The genioglossus muscle exhibits complex neural control, receiving simultaneous inspiratory, expiratory, and tonic drives even during quiet breathing.
- Further research is needed to fully elucidate the neural drive to human respiratory muscles across various tasks and disease states.
More Related Videos
11:07In Vivo Intracellular Recording of Type-Identified Rat Spinal Motoneurons During Trans-Spinal Direct Current Stimulation
Published on: May 11, 2020
06:08Assessing Rat Diaphragm Motor Unit Connectivity Outcome Measures as Quantitative Biomarkers of Phrenic Motor Neuron Degeneration and Compensation
Published on: April 19, 2024
Related Concept Videos
01:18Neural Control of Respiration
The neural regulation of respiration is a meticulously coordinated process primarily controlled by the respiratory centers located within the brainstem. These centers, composed of specialized neurons, transmit nerve impulses that control the contraction and relaxation of our respiratory muscles.
Respiratory Centers in the Brainstem
Two primary areas comprise the respiratory center: the medullary respiratory center in the medulla oblongata and the pontine respiratory group in the pons. The...
Respiratory Centers in the Brainstem
Two primary areas comprise the respiratory center: the medullary respiratory center in the medulla oblongata and the pontine respiratory group in the pons. The...
01:20Motor Unit Stimulation
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...
01:22Physiology of Respiration II: Neurogenic Control of Respiration
The neurogenic control of respiration coordinates various neural networks and pathways to regulate breathing rate and depth, meeting the body's oxygen and carbon dioxide exchange requirements. This system adapts to physiological and environmental conditions, ensuring optimal breathing patterns.
Central Control
The brainstem is the primary site of central control, hosting respiratory centers:
Central Control
The brainstem is the primary site of central control, hosting respiratory centers:
01:19The Neuromuscular Junction
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...
01:29Relaxation of Skeletal Muscles
The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions in the sarcoplasm, and the availability of energy or ATP to support contractions.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
01:24Generation of Action Potential in Skeletal Muscles
Every cell in the body maintains a membrane potential due to an uneven distribution of positive and negative charges across its plasma membrane. The membrane potential is measured in millivolts and quantifies the difference in charge across the membrane.
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the cell's...
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the cell's...