In a study published recently in the Journal of Neuroscience, UCLA neurology professor Paul Thompson and colleagues used a new type of brain-imaging scanner to show that intelligence is strongly influenced by the quality of the brain’s axons, or wiring that sends signals throughout the brain. The faster the signaling, the faster the brain processes information. And since the integrity of the brain’s wiring is influenced by genes, the genes we inherit play a far greater role in intelligence than was previously thought.
What the study found was that myelin thickness corresponds to intelligence. That is, the more fatty covering of the axons in your brain, the more intelligent you are likely to be. And because myelin thickness is genetically linked, intelligence has a genetic link.
What’s important to remember here is that intelligence isn’t soley about genetics. We are not our genes. Environmental influences are still overwhelmingly strong in determining intelligence. Take the South. I doubt there’s really such a large contingent of people with thin myelin gathered below the Mason-Dixon line. It’s more likely a lack of education funding and general principles praising intellectual achievement (see last 50 thousand election cycles, especially the last three national elections).
Because the myelination of brain circuits follows an inverted U-shaped trajectory, peaking in middle age and then slowly beginning to decline, Thompson believes identifying the genes that promote high-integrity myelin is critical to forestalling brain diseases like multiple sclerosis and autism, which have been linked to the breakdown of myelin.
Weird how science does good things.