Studies show that many brain areas are affected by drugs of abuse. The prefrontal cortex (PFC), however, plays an especially pivotal role in how addiction is manifested. Studies of addicted individuals show they have a reduced capacity to perform PFC dependent tasks, such as working memory (a process using multiple memory systems to facilitate problem solving and choose appropriate behaviours). Human studies also show abnormal activity patterns of the PFC in addicted individuals. When tested during withdrawal, the PFC of addicts remains inactive in response to cues that signal the delivery of natural rewards, such as food. In contrast, when they are given a cue that signals the delivery of a drug reward, addicts show both increased activation of their frontal areas and a high level of self-reported drug craving. Taken together, these data suggest an important component of compulsive drug taking. Linking the behavioural changes that an addict goes through to the underlying physiological changes that neural networks undergo is important for understanding the neurobiology of addiction. Dr. Christopher Lapish is studying the behavioral and neurophysiological changes that characterize the addicted state. His experiments will help delineate the neurophysiological changes that occur in the PFC during the process of addiction. By identifying the specific brain patterns that are induced by addiction, he hopes his work will result in a powerful tool to assess specific pharmacological treatments that may abolish them.