How is PET useful in the study of brain functioning?

Positron emission tomography (PET) scans can show the functioning of the brain by measuring cerebral blood flow. PET scans produce a picture of activity and of function. A person is administered a small amount of radioactive glucose. The area of the brain that is active uses the glucose more quickly, and this is reflected in the image that the computer constructs. Neuroimaging techniques using PET can present a picture of brain activity associated with cognitive processes like memory and the use of language. PET scans are used to study the chemical and physiological processes that take place in the brain when a person speaks correctly or stutters, and they can show the specific brain activity associated with schizophrenia, manic depression, posttraumatic stress disorder, and obsessivecompulsive disorder. In addition, they have shown the precise area of the brain that malfunctions in certain mental illnesses as well as the effects of drugs, such as Prozac, and traditional talking therapy on nerve cells.