Shift from goal-directed to habitual cocaine seeking after prolonged experience in rats.

The development of drug-seeking habits is implicated in the transition from recreational drug use to addiction. Using a drug seeking/taking chained schedule of intravenous cocaine self-administration and reward devaluation methods in rats, the present studies examined whether drug seeking that is initially goal-directed becomes habitual after prolonged drug seeking and taking. Devaluation of the outcome of the drug seeking link (i.