Taken together, the main effect of cocaine (and other stimulants such as MPH) on the PFC is to increase PFC activity, as measured by glucose metabolism, CBF or BOLD (although in a recent study, cocaine reduced PFC cerebral blood volume in macaque monkeys20). As the length of access to the drug and drug expectation modulate PFC activity, increases in activity that occur during drug administration may be indicative of the neuroplastic adaptations that ensue in the transition from first or occasional use to regular use, such that drug-related neuropsychological processes, including drug-related anticipation (and other conditioned responses), suppress or eclipse non-drug related processes, such as anticipation of — or the motivation to — pursue non-drug related goals (FIG. 3).
