Practice changes the primary motor cortex of brain so that it can become an important substrate for the storage of motor skills, find researchers.
Researchers from the University of Pittsburgh School of Medicine showed that practice leads to decreased metabolic activity for internally generated movements, but not for visually guided motor tasks, and suggest the motor cortex is "plastic" and a potential site for the storage of motor skills.
Senior investigator Peter L. Strick said that their observation has suggested that extensive practice and the development of expert performance induces changes in the primary motor cortex.
The researchers found that markers of synaptic activity display a marked decrease in monkeys trained to perform sequences of movements that are guided from memory - an internally generated task - rather than from vision.
Scientists recorded neuron activity and sampled metabolic activity, a measure of synaptic activity in the same animals, to examine if the change in synaptic activity indicated that neuron firing also declined.
All the monkeys were trained on two tasks and were rewarded when they reached out to touch an object in front of them. In the visually guided task, a visual target showed the monkeys where to reach and the end point was randomly switched from trial to trial.
In the internally generated task the monkeys were trained to perform short sequences of movements without visual cues. They practiced the sequences until they achieved a level of skill comparable to an expert typist.
The researchers found neuron activity was comparable between monkeys that performed visually guided and internally generated tasks. However, metabolic activity was high for the visually guided task, but only modest during the internally generated task.
It was concluded that practicing a skilled movement and the development of expertise leads to more efficient generation of neuron activity in the primary motor cortex to produce the movement.
The study was published online in journal Nature Neuroscience.