Researchers have found an intriguing association: they "compared how quickly a group of males ranging in age from 23 to 80 could perform a motor task and then correlated their performances to their brains' myelin integrity. The researchers found a striking correlation between the speed of the task and the integrity of myelination over the range of ages. Put another way, after middle age, we start to lose the battle to repair the myelin in our brain, and our motor and cognitive functions begin a long, slow downhill slide. ... speed of a movement increases with the frequency of neuronal action potential (AP) bursts in the brain ... Fast movements require high-frequency AP bursts that depend on excellent myelin integrity over the entire axon network involved in controlling that movement ... the research suggests that the myelin breakdown process should also reduce all other brain functions for which performance speed is dependent on higher AP frequencies, including memory; it also supports the suggestion that myelin breakdown is a biological process of aging underlying the erosion of physical skills and cognitive decline." The question now becomes "why exactly does this decline in myelin happen, and what can be done to reverse it?"