Yifei Sun

The brain is like a sprawling city: districts-regions communicate via streets-neural pathways. If traffic lights at an intersection fail, traffic grinds to a halt. Similarly, in the brain, when bundles of nerve fibers (white matter) malfunction, distant regions stop working in concert, and thought stalls.

Ultrasound isn't just for baby pictures on a screen. It can scan muscles and tendons, but there's a catch: bones. To sound waves, they act like mirrors to light. The reflection is so strong that nothing behind them is visible.