Abstract
In laboratory animals, repeated cocaine exposure produces long-lasting behavioral alterations such as psychomotor sensitization and conditioned place preference (CPP) that are thought to model various aspects of addictive behavior. A great deal of effort has gone into examining the relationship of electrophysiological, and particularly synaptic alterations, to psychomotor sensitization and CPP. Many of these studies have focused on alterations within the nucleus accumbens because it is one of the main targets of the mesolimbic dopamine system that originates with dopamine neurons in the ventral tegmental area (VTA) and is critical for many cocaine-induced behaviors. Medium spiny neurons (MSNs), which are the majority of nucleus accumbens neurons, also receive significant glutamatergic inputs from the prefrontal cortex, basolateral amygdala, and hippocampus that convey information about drug-associated environmental stimuli. Thus electrophysiological and synaptic alterations within nucleus accumbens MSNs are likely to affect sensitization and CPP behavior.