Srinagar, May 13 -- In a sleepy Kashmir village, a young stargazer looked up at the night sky, chasing questions larger than his world: Why does the mind forget? Where does illness hide in the brain? What lies beneath thought itself?

That Pulwama boy, Mudasir Maqbool, is now a scientist at the U.S. National Institutes of Health (NIH), where he crafts radiotracers: tiny chemical tools that light up the brain's hidden processes.

His work helps researchers study Alzheimer's, Parkinson's, depression and other diseases that remain among the greatest medical mysteries of our time.

In the sterile calm of NIH's Molecular Imaging Branch in Bethesda, Maryland, Dr. Mudasir's path has been anything but linear. But his trajectory is reshaping how s...