TITLE: Deconstructing skill learning and its physiological mechanisms
FIVE KEY IDEAS
Different brain regions are responsible for learning different components of a motor skill, and they work together as a network to facilitate the learning process.
The cerebellum contributes to learning motor tasks, particularly for error-based learning mechanisms, as shown by changes in cerebellar plasticity during the learning of a new sensorimotor map.
Motor learning occurs through the refinement of movement through the gradual reduction of errors. This process is thought to involve the gradual strengthening of certain synapses and the weakening of others, which allows for more precise control of movement.
M1 plasticity is involved in learning a motor sequence but not in learning a sensorimotor map.
The cerebellum interacts with the prefrontal cortex and basal ganglia, and future research is needed to better understand how these brain regions interact during motor skill learning.
TERMINOLOGY
Brain network: the interconnected nodes in the brain that work together to perform motor skills.
Brain stimulation interventions: interventions that target specific brain regions to modulate motor learning.
Cerebellum: a brain region involved in acquiring and maintaining internal models that predict the sensory consequences of our actions.
Corticospinal excitability: a measure of the excitability of the corticospinal tract, which controls voluntary movement.
Long-term potentiation (LTP): a mechanism of synaptic efficacy in which repeated movement patterns can alter the output organization of M1.
Motor components: the different parts involved in motor skill acquisition, including the internal representation and sequence of movements.
Motor skill acquisition: the process of learning how to interact with objects or surroundings and coordinate movements to perform a particular skill.
Neurophysiological processes: the physiological mechanisms underlying motor skill acquisition, such as plastic changes in the cerebellum and primary motor cortex (M1).
Non-invasive brain stimulation: a technique used to identify the physiological contributions of different brain regions in learning motor components.
Occlusion: a method used to assess the presence of LTP-like plasticity in M1.
Primary motor cortex (M1): a brain region involved in encoding movement sequences.
Plasticity: the ability of the brain to change its structure and function in response to experience or stimulation.
Sensorimotor map: formed in the brain as a result of repeated sensorimotor experiences, and it helps individuals to develop accurate and efficient movement patterns
Abstract
To acquire complex motor skills, individuals must learn different motor components, including the internal representation and the sequence of movements. However, the specific neurophysiological processes underlying the acquisition of these components are not well understood. In this study, researchers used non-invasive brain stimulation to identify the physiological contributions of the cerebellum and primary motor cortex (M1) in learning these components. They found that plastic changes in the cerebellum, but not in M1, are linked to learning the internal representation, while both cerebellar and M1 plasticity mediated movement sequence learning. The results suggest that learning different components of a motor skill engages multiple nodes of the brain network and that targeting specific brain regions with brain stimulation may not always have positive results.
Mastering a motor skill, such as hitting a baseball, requires the brain to learn how to interact with new objects or surroundings, such as the weight of a bat, and coordinate a smooth sequence of movements. This learning process involves multiple brain areas, each responsible for acquiring different motor components using different physiological processes.
To perform smooth and accurate movements, our brain relies on internal models that predict the sensory consequences of our actions. Research has shown that the cerebellum plays a crucial role in acquiring and maintaining these internal models. Additionally, the primary motor cortex (M1) is involved in encoding movement sequences and can rapidly alter its output organization with repeated movement patterns through mechanisms of synaptic efficacy such as long-term potentiation (LTP).
While the cerebellum is important for acquiring and maintaining internal models, and the M1 is active in encoding movement sequences, the specific roles of each region in learning individual motor skill components have not been fully disentangled. Some studies have suggested that interventions targeting both the cerebellum and M1 can lead to greater improvements in motor learning compared to interventions targeting only one brain region. However, other studies have shown that targeting a single brain region can be effective for specific types of motor learning. Thus, further research is needed to determine the most effective strategies for modulating motor learning through brain stimulation interventions, taking into account the specific skill being learned and the individual's characteristics.