Abstract
Many reports show that repeated cocaine administration increases dendritic spine density in medium spiny neurons of the nucleus accumbens, but there is less agreement regarding the persistence of these changes. In this review we examine these discrepancies by systematically categorizing papers that measured cocaine-induced changes in accumbal spine density. We compare published reports based on withdrawal time, short versus long duration of cocaine administration, environmental pairing with cocaine, and core/shell subregion specificity. Together, these studies suggest that cocaine exposure induces rapid and dose-dependent increases in spine density in accumbens neurons that may play a role in the maintenance of cocaine use and vulnerability to early relapse, but are not a factor in behavioral changes associated with longer abstinence.