pick someone’s brains—get ideas or information about a subject by asking a person:
- I would love to pick your brains, so to speak, and see what kind of innovative ideas you could come up with.
Note: The expression does not correlate in meaning with the phrase brain someone—(sl.) hit smb. hard on the head (often used as a threat):
- The constable threatened to brain him if he didn’t shut up.
prey on someone’s mind —(of anxieties, losses, etc.) afflict or worry a person:
- When the servants had withdrawn, I found that the unhappy result of the duel was still preying on his mind.