Dissociating experience-dependent and maturational changes in fine motor function during adolescence

Adolescence is a sensitive period in motor development but little is known about how long-term learning dependent processes shape hand function in tasks of different complexity. We mapped two fundamental aspects of hand function: simple repetitive and complex sequential finger movements, as a function of the length of musical instrumental training. We controlled maturational factors such as chronological and biological age of adolescent female participants (11 to 15 years of age, n=114). We demonstrated that experience improves performance as a function of task complexity, the more complex task being more susceptible for experience driven performance changes. Overall, these results suggest that fine motor skills involving cognitive control and relying on long-range functional brain networks are substantially shaped by experience. On the other hand, performance in a simple repetitive task that explains fine motor speed is primarily shaped by white matter development driven by maturational factors.