While a different program, Google's Engineering Residency reportedly pays about $100k, depending on location. I would imagine that the Brain Residency pays something comparable.
Aye. True story.
(in case it's not clear, Cinjon is a current brain resident.) And yes - brain residents are full-time engineers and paid as such.
They came to do a recruitment talk at my university. Per the spokesperson, they pay exactly the same as any other introductory job at google (so a hell of a lot more than academia).