The Brain's Gray Matter

 

The left hemisphere of the brain contains more gray matter. Gray matter is brain tissue that has fewer of the neuronal axons wrapped with the whitish insulation known as myelin. This contributes to the slightly pinkish-gray color of the left hemisphere. Gray matter sends messages at a slower rate than white matter. Some estimates are that gray matter transmission speeds in the left hemisphere are up to 275 mph approximately, while white matter transmission speeds in the right hemisphere can reach 600 mph. Convention wisdom has been that when it comes to brain health and brain function, gray matter (the neurons that form the cerebral or thinking  cortex) is more important than white matter (the myelin covered axons that physically connect neuronal regions in the brain)—perhaps because left-hemisphere functions are more valued in many industrial societies over right-hemisphere. More tomorrow.