Peter Hall didn't notice when the proteins in his brain started to change. He noticed other things: a vague depression, general anxiety, sudden mood swings. But blaming any of that on brain chemicals wouldn't have occurred to him.
The proteins in Hall's brain were changing, however. Ordinarily made up of tiny strands of intertwined amino acids, the complex molecules had begun to assume a very different shape, collapsing into sticky sheets. Before long, these gummy structures began to clump sloppily together, creating pits and divots where there had once been vital brain tissue. Within months Hall was delusional and bedridden. Not...