New Brain Connections Form Rapidly During Motor Learning

The following article is well worth reading in full, it covers experiments that help explain why learning certain types of skills, like riding a bike, are remembered over many years even when not using those skills.

New Brain Connections Form Rapidly During Motor Learning
[...]
When previously trained mice were reintroduced to the reaching task four months later, their skill at the task remained high, and images of their brains did not show increased spine formation. When previously trained mice were taught a new skill, however, they showed enhanced spine formation and elimination similar to that seen during the initial training. Furthermore, spines that had formed during the initial training persisted after the remodeling process that accompanied the learning of a new task.

These findings suggest that different motor behaviors are stored using different sets of synapses in the brain, Zuo said. One of the questions she would like to explore in future studies is how these findings apply to different types of learning.
[...]