The last two decades have seen prodigious growth in the application of
brain imaging methods to questions of substance abuse and addiction.
Despite considerable advances in our understanding of the central
effects of drugs provided by preclinical data, relatively little direct
evidence was known of how substances of abuse affect the brain and other
eNS processes in humans. Brain imaging techniques have allowed access to
the human brain and enabled the asking of questions never before
imagined. The positron emission tomography (PET) data ofVolkow and her
colleagues in the late 1980s, showing the uptake and time course of
cocaine's binding in the human brain, revealed for the first time the
distinct sites of action of this drug. This work was extremely important
because it showed clearly, through imaging a drug in the brain of a
living human, that the time course of its action paralleled the
behavioral state of "high. " This study marked a turning point in our
understanding of drug-brain-behav- ior interactions in humans. Many more
investigations of drug effects on the structure and function of the
human brain were soon to follow, leading to much better insights into
brain systems. Brain imaging allowed for the direct assessment of
structural and functional anatomy, biology, and chemistry in substance
abusers.