Beyond their rapid rewarding effects, drugs of abuse can durably alter an individual's
response to their environment as illustrated by the compulsive drug seeking and risk of
relapse triggered by drug-associated stimuli. The persistence of these associations even
long after cessation of drug use demonstrates the enduring mark left by drugs on brain
reward circuits. However, within these circuits, neuronal populations are differently affected
by drug exposure and growing evidence indicates that relatively small subsets of neurons …