This MRI map of the human brain highlights variations in myelin content across the brain's cortex. Myelin acts as insulation around brain cells, allowing electrical signals to travel quickly and reliably. The red and green regions indicate more myelin, typical of areas handling rapid sensory or motor processing. The blue and purple regions have less myelin and are often involved in integrating information across many brain systems. Together, these patterns reveal how the brain balances speed and flexibility in its wiring.