It's only a matter of time: longevity of cocaine-induced changes in dendritic spine density in the nucleus accumbens

- Accumbal dendritic spine changes are observed within 1-3 days of the 1st cocaine use.
- Three-11d of cocaine leads to short-lived spine increases that are lost after 1-month.
- 12-37d of cocaine leads to spines that may remain after 1-month of withdrawal.
- Spine changes are more prevalent and longer lasting in the shell than the core.
- No increases in dendritic spines persist for 90 days after cocaine.

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.