The year was 2002, and 10-year-old Spencer Neff was a spunky boy with hydrocephalus, a buildup of cerebrospinal fluid inside his brain. A surgically implanted shunt – a tube to drain the fluid – was in place. Like all children with shunts, he was at risk for having the shunt plug up and malfunction, and he sometimes got scary headaches. But Spencer was lucky to have a neurosurgeon uncle, Samuel Neff, who offered him an interesting proposition:  would you rather be paid to help with some research, or be a scientific collaborator?  Spencer chose the latter. …