Brain activity peaks at 39 - downhill after that...

For those of us over 39 years of age, I am not too sure if you want to carry on reading this post after this point… Researchers at UCLA have concluded that neuronal myelination (the formation of myelin sheath around a neuron fostering fast signaling bursts in the brain) peaks at the age of 39 and then goes downhill after that.

The myelination of brain circuits follows an inverted U-shaped trajectory, peaking in middle age. Bartzokis and others have long argued that brain aging may be primarily related to the process of myelin breakdown.

The test they used was a little strange sounding to the layperson, but I guess it makes perfect sense in neuroscience circles...

To test their hypothesis, they used one of the simplest and best understood tests of central nervous system processing speed: how fast an individual can tap their index finger. The results supported what the researcher had suspected, that finger-tapping speed and myelin integrity measurements were correlated and "had lifespan trajectories that were virtually indistinguishable," according to Bartzokis. And yes, they both peaked at 39 years of age and declined with an accelerating trajectory thereafter.

Looks like we have downhill trajectory after 39:

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.. Beginning in middle age, the process of age-related myelin breakdown slowly erodes myelin's ability to support the very highest frequency AP bursts. That may well be why, besides achy joints and arthritis, even the fittest athletes retire and all older people move slower than they did when they were younger.

All hope should not be lost though...

Since in healthy individuals brain myelin breakdown begins to occur in middle age, there is a decades-long period during which therapeutic interventions could alter the course of brain aging and possibly delay age-driven degenerative brain disorders such as Alzheimer's

My opinion: Finger tapping and intelligence are two completely different things. While on the one hand, finger tapping denotes physical dexterity and to some extent can be correlated to neuronal firing frequencies, intelligence (as yet qualitatively or quantitatively immeasurable) in many cases is not a measure of physical dexterity, but an amalgam of experience, environment and neuronal activity. This study certainly excludes the first two factors – life experiences and the effects of ones environment… Again, my humble opinion…