They use a number of different procedures that map out parts of the brain. The glucose soon enters the brain, which absorbs the solution.
Sensors detect the consumption rate and display the active region on a computer screen.
Surgeons sometimes use a more invasive method of brain mapping, electrically stimulating different sections of the brain during surgery. The brain is not sensitive to pain, so a patient can be awake during this procedure. As a surgeon stimulates one part, the patient could say what he or she is experiencing. Regardless of the procedure used, scientists have gained tremendous insight as to how the brain works.