Extinction and Reinstatement of Responding for METH. (A) The number of nose-pokes over 7 days of extinction training (solid line: active nose pokes, dotted line: inactive nose pokes). (*p<0.05, difference between individually and socially housed females). B) Cue and METH-induced (0.18 mg/kg) reinstatement of drug seeking measured with the number of active nose pokes. Different letters above the bars indicate a significant difference between days, within each housing condition (a,b,c) *p<0.05: difference between individually and socially housed females.