The Brain's White Matter

I just heard on the news that after a stroke or other traumatic brain injury, the damage to the white matter is a better predictor “of outcome” than gray matter. What does this mean? I’m not even sure I know the difference between gray and white matter. Actually, I'm pretty sure I do not know!

 

Great question! Let’s start with the difference between gray and white matter. The largest projection from a neuron or thinking cell is the axon, by which information leaves the neuron. The right hemisphere contains more white matter. That is, it has more neuronal axons that are wrapped with a whitish insulation (think fiberoptics) known as myelin. Reportedly, this helps prevent electricity from leaking out and increases the speed at which information messages fly along the neuron highways. This also gives the right hemisphere it’s slightly pinkish-white color.  More tomorrow.