How does the brain change with the practice and the acquisition of skill? In a recent paper published in Nature Neuroscience, Nathalie Picard, Yoshiya Matsuzuka, and Peter Strick looked at neural activity in monkeys who had trained from one to six years in performing sequential movements. Examining activity of the primary motor cortex (M1), the researchers found that the metabolic activity in M1 was greatly reduced for internally generated motor tasks compared to visually guided tasks. The authors conclude that the low metabolic activity was a consequence of the animal’s training leading to high levels of motor skill in the internally generated tasks. Interestingly, while the metabolic activity of M1 was reduced, neural activity was not reduced relative to the visually guided task. Thus, while metabolic and neuron activity were positively correlated for the visually guided task, they were decoupled for the internally generated task. These results provide direct evidence for a widespread alteration in the relationship between metabolic and neuron activity associated with practice on a sequence of movements. Further, they suggest that practice leading to skilled performance results in more efficient generation of neuronal activity in M1. Low activation is not always a sign of low neuronal activity. Instead, it may be a reflection of plastic mechanisms involved in the development of expertise.
The Paper is available here.