The phrase "a functioning brain" is correct and usable in written English.
It can be used when discussing cognitive abilities, mental health, or the general state of someone's mental faculties.
Example: "To solve complex problems, one must have a functioning brain and the ability to think critically."
Alternatives: "an active mind" or "a healthy brain".
"You need a functioning brain.
You're a rational person with a functioning brain, so you're assuming I included that as some sort of humorous exaggeration.
Any American president with a functioning brain would be tough on Pakistan, especially as far as drones are concerned".
The worst imaginable horror for my mother was that she might be kept alive by expensive and painful procedures when she no longer had a functioning brain.
Accurately simulating a functioning brain from a static circuitry map, many scientists say, will require a grasp of how living brains work that is orders of magnitude better than what we have today.
Although it ultimately reaffirmed the validity of brain death, it abandoned the biological and philosophical justification presented by the 1981 President's Commission that a functioning brain was necessary for the body to operate as an "integrated whole".
Every bit as potent as when it first appeared in 1961, McCaffrey's tale introduces us to Helva, a girl who is "born a thing" with a badly disabled body but a fully functioning brain; she is spared euthanasia and made the living CPU of a spaceship.
Most of us, however, do not treat middle-of-the-night awakenings as a sign of a normal, functioning brain.
The front half will grow a new tail and, more impressively, the back half will grow a new head complete with a fully functioning brain.
Medicine may progress by analysing the brain, but - he insists - what philosophers need to explain is the mind, which is a different thing altogether, however much it depends on a properly functioning brain.
