There’s plenty of already existing evidence for the nature of linguistic categorization and prototype theory. I laid much of it out in my (old) discussion of middle voice several years ago, where I explain categorization and cognitive linguistics in the context of discussions of middle voice.
But there’s a recent article on lexical semantics from a group of researchers at UC Berkeley using fMRI scans of people’s brains to map out how lexemes light up the brain. The result is fascinating and beautiful. It also provides additional compelling data for how the relationship between metaphor and meaning is realized neurologically.
On a more “linguisticky” note, if Jack Gallant and his research team work here had been possible in the 1970’s, the linguistic wars wouldn’t have ended they way they did. It’s a solid affirmation, too, of the models put forward in Langacker’s Foundations of Cognitive Grammar.