Data are mean (± SEM) Difference score calculated as time spent in the drug-paired compartment minus time spent in the vehicle-paired compartment (A) or activity (cm) following the first and last drug injection (B). For drug-paired sessions during conditioning, animals received an s.c. injection of AT-1001 10 minutes prior to receiving an injection of 30 mg/kg cocaine and were placed immediately into their designated compartment. Vehicle controls received two injections 10-min apart and animals were placed into test compartments immediately following the second injection. *, P<0.05, significant difference from vehicle controls. △, P<0.05, significant difference from cocaine alone.†, P<0.05, significant difference from the first injection.