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Cambios rápidos en el rendimiento de las neuronas únicas de la corteza motora a la actividad muscular
Adam G Davidson1, Vanessa Chan, Ryan O'Dell
1Departments of Neurology and Neurobiology and Anatomy, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
Science (New York, N.Y.)
|December 22, 2007
Resumen
La reorganización de la corteza motora implica cambios en la conectividad funcional de las neuronas a los músculos. Este estudio revela cambios rápidos y dinámicos en el rendimiento, lo que indica plasticidad más allá de la propia corteza motora.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- El control del motor es el control del motor.
- La neuroplasticidad es la neuroplasticidad.
Sus antecedentes:
- La corteza motora exhibe una reorganización significativa a través de la modulación de la excitabilidad.
- Las investigaciones anteriores se centraron en los cambios corticales, dejando la reorganización extracortical menos entendida.
Objetivo del estudio:
- Investigar si la reorganización de la corteza motora se extiende al rendimiento de las neuronas individuales de la corteza motora a la actividad muscular.
- Explorar los cambios en la conectividad funcional más allá de la corteza durante una tarea que incentiva una mayor potencia motora.
Principales métodos:
- Se registra la actividad de una sola neurona de la corteza motora y la correspondiente actividad muscular.
- Utilizó un paradigma conductual diseñado para fomentar una mayor conectividad funcional.
- Analizó el rendimiento de corta latencia de las neuronas a los músculos en diferentes épocas de comportamiento.
Principales resultados:
- El rendimiento de latencia corta observado de las neuronas registradas a la actividad muscular que varió entre las épocas de comportamiento.
- Estos cambios en el rendimiento no se explicaron consistentemente por el aumento de la velocidad de disparo de las neuronas, la actividad muscular en curso o la sincronización neuronal.
- Demostró que la conectividad funcional entre las neuronas de la corteza motora y los grupos de alfa-motoneuronas puede cambiar rápidamente.
Conclusiones:
- La reorganización de la salida de la corteza motora implica rápidas alteraciones en la conectividad funcional a nivel de una sola neurona a nivel muscular.
- Estos hallazgos sugieren que la neuroplasticidad significativa ocurre más allá de la corteza motora, afectando el control motor.
- El estudio destaca los cambios dinámicos en el rendimiento del sistema motor, ofreciendo nuevos conocimientos sobre el aprendizaje motor y la adaptación.
Videos de Conceptos Relacionados
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...
01:22Muscle Stimulation Frequency
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...
01:15Muscle Contraction
01:10Muscle Contraction
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 muscle...
01:13Motor Units
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...
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...