Definition of pick someone's brains (or brain) in English:

pick someone's brains (or brain)

phrase

informal
  • Obtain information by questioning someone who is better informed about a subject than oneself.

    ‘mind if I pick your brain for a minute?’
    • ‘I want to pick your brain on some other issues of the day first.’
    • ‘He knew the business side so I picked his brain on that subject.’
    • ‘We picked their brains about the impact on soaring house prices, and the damage caused by the North / South divide.’
    • ‘He waited 13 years between making his first short film and his second, but that wouldn't happen today, when people with ideas sit beside him on the bus and start picking his brains.’
    • ‘They send us questionnaires to pick our brains.’
    • ‘Since I was not even remotely interested in purchasing comics, I spent the next hour picking his brain.’
    • ‘I tried to pick their brains for any better solutions on how to go about changing the law or simply fixing my own problem.’
    • ‘Thanks for being so kind and letting me pick your brain.’
    • ‘‘They may be coming to see us,’ she laughs, ‘but I'll certainly take the opportunity to pick their brains.’’
    • ‘The quiz master joined us and we tried to pick his brain about where he gets his questions from.’