The brain never stops changing and it can adapt to new circumstances and environments over the course of an individual's life. This adaptability is called neuroplasticity or neural plasticity. One example of this adaptability occurs in musicians, particularly pianists, guitarists, and other musicians who work with stringed instruments. Over time, the relative number of neurons related to each finger in the motor cortex increases. This allows for more dexterity in the fingers. This is connected to the individual's actual practice as guitarists show this increase only with regard to the fingers on their fret hand.
Neural plasticity is also important in the acquisition of new language abilities and in the ability to learn within new areas of knowledge. Even late in life, this information can be acquired, which necessitates the reorganization of neuronal pathways. Reorganization is necessary because, biologically, an individual stops creating neurons in their teens. Children generally increase the number of neurons in their brains through adolescence until their late teens. This is why children can so quickly and effectively pick up new skills and information. During their early 20s, an individual goes through a pruning process in which neuronal connections are reduced for those skills and bits of information which are rarely used. This is less a reduction in neuronal activity and a reorganization to prioritize and strengthen frequently used pathways. However, an individual's brain is never set or static. It is always responding and adapting to new information.