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.
Intriguing article but frustratingly vague on the measurements used for intelligence testing. Apparently HARDI (High Angular Resolution Diffusion Imaging) can measure the diffusion of water through the brain, especially myelin. In yet another twin study (n=46 pairs) there appears to be a correlation between diffusion speed and intelligence.
