plus:
头脑 is usually used like that:头脑风暴 brainstrom(not the disease,the sprak get into your head suddenly),头脑灵活somebody do sth pretty agile,do not do everything by the book.
so 头脑+adj./n.
脑子 is usually used like that:用脑子 use brain(think about that before you do sth,so you would not fail or do not seem stupid on that)脑子好用 you are good at thinking,present some good idea 脑子有病/脑子有问题(脑子+verb phrase)you did sth but sb think that the method of work is unbelievable,sb cannot accept that.
so v.+脑子 or 脑子+adv.+v
大脑 the physical stuff in head