Functional imaging of craving

To visualize brain activity associated with mental states, such as craving for alcohol and other drugs (AODs), researchers have begun to use functiona l imaging techniques. Three commonly used techniques are single photon emis sion computed tomography (SPECT), positron emission tomography (PET), and f unctional magnetic resonance imaging (fMRI). Studies using these three appr oaches have been reviewed in order to evaluate the validity of a proposed m odel of the brain regions involved in alcoholism and the craving for alcoho l. This model suggests a central role for a connected group : of brain regi ons that include the basal:ganglia, thalamus, and orbital cortex. A study u sing SPECT technology in alcoholics, however, found altered brain activity in only some of those regions during craving. Additional studies in alcohol ics, as well as cocaine users, identified several other brain regions whose activities appeared to change in response to :craving, These studies have led to the development of a revised model of brain regions involved in crav ing for AODs. Numerous questions remain, however, that must be-answered bef ore the brain areas involved in craving can be identified conclusively.