Related Experiment Video
Updated: Jul 20, 2025
09:48
Intracortical Inhibition Within the Primary Motor Cortex Can Be Modulated by Changing the Focus of Attention
Published on: September 11, 2017
10.0K
Gravity-efficient motor control is associated with contraction-dependent intracortical inhibition
Nicolas Gueugneau1, Alain Martin1, Jérémie Gaveau1
1INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000 Dijon, France.
Iscience
|August 3, 2023
Summary
Understanding how the brain controls arm movements against gravity is key. This study reveals specific brain activity changes during shortening versus lengthening muscle contractions, offering insights into efficient motor control.
Area of Science:
- Neuroscience
- Human Motor Control
- Biomechanics
Background:
- Efficient human movement, particularly along the gravity axis, relies on distinct muscular contraction modes.
- While the necessity of shortening and lengthening contractions is known, the underlying neuromuscular control mechanisms remain unclear.
Purpose of the Study:
- To investigate the neural control mechanisms governing arm movements influenced by gravity.
- To identify modulations in cortical, spinal, and muscular outputs during vertical arm movements.
Main Methods:
- Neurophysiological experiments were conducted to monitor brain and muscle activity.
- Corticospinal excitability, intracortical inhibition, and spinal motoneuron responsiveness were assessed during controlled arm movements.
Main Results:
- A significant decrease in corticospinal excitability was observed during lengthening contractions compared to shortening contractions.
- Increased intracortical inhibition was noted during lengthening contractions.
- Spinal motoneuron responsiveness remained unchanged across different contraction types.
Conclusions:
- The findings suggest gravity-tuned motor control is supported by feedforward mechanisms.
- Contraction-dependent modulations in supraspinal motor output offer a new perspective on optimizing movements along the gravity axis.
Related Concept Videos
01:20Motor Unit Stimulation
1.6K
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...
1.6K
01:18Hierarchy of Motor Control
2.9K
The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
2.9K
01:22Indirect Motor Pathways
1.6K
The indirect motor or extrapyramidal pathways originate in the brainstem, the lower portion of the brain that connects it to the spinal cord. They consist of several distinct tracts, each with specialized functions. The four main tracts of the indirect motor pathways are the vestibulospinal tract, the reticulospinal tract, the tectospinal tract, and the rubrospinal tract.
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...
1.6K
01:13Motor Units
4.1K
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...
4.1K
01:05Mechanism of Ciliary Motion
3.7K
The ciliary structures were first seen in 1647 by Antonie Leeuwenhoek while observing the protozoans. In lower organisms, these appendages are responsible for cell movement, while in higher organisms, these appendages help in the movement of the extracellular fluids within the body cavities.
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
3.7K
01:11Direct Motor Pathways
2.1K
The direct motor pathways, also known as the pyramidal tracts, are a group of neural pathways that originate in the brain and descend through the spinal cord. They control the voluntary movement of the body. There are two major direct motor pathways: the corticospinal and the corticobulbar tracts.
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...
2.1K