I just read Ted Chiang's short story "Understand", which is in this collection.

It's about a guy, Leon Greco, who suffers extensive brain damage after falling through the ice and nearly drowning. He's given an experimental drug that regenerates neurons, and it works so well his intelligence begins to grow by leaps and bounds. How does this work? The glossed-over explanation is that it produces more dendrites (those are basically the inputs to neurons). It's kind of hard to see how having more dendrites would vault you to superintelligence, but whatever.

The story is kind of like Flowers For Algernon, although instead of his intelligence rising, peaking, and then falling again, Greco's intellect just keeps on skyrocketing (partly due the fact that he keeps stealing more of the drug and injecting himself with it).

But while Flowers was more interested in examining the emotional effects and social impact of intelligence manipulation, on the protagonist and those around him, "Understand" is more like a clinical speculative exercise in what it would be like to have an exponentially-increasing intelligence. Greco doesn't have close living relatives or friendships. His intellect soars so high so fast that he begins to view other humans like ants. He begins composing his own arcane poetry, devising engineering problems and solving them just as an exercise, and eventually inventing his own language because English is no longer expressive enough for him.

He also gains increasing mastery over his motor control, his heartbeat, breathing, and reflexes. And eventually he learns how to control other people's nervous systems at a distance, so that he becomes a kind of psychic warrior.

I read it straight through, and really wanted to see what happened next, but in the end I didn't really think it was one of Chiang's stronger stories. The Story of Your Life, for example, was much better, because it engaged emotionally. It was more of a story and less just a conceit. Still, just about anything Chiang writes is worth reading, so if you haven't checked out his stuff, you should.