Psychopharmacology · 2002 · 172 citations · 0 references
MedicineBehavioral SciencesPharmacologyBehavioral PharmacologyNeuropharmacologyPsychopharmacologyAddictionAddiction NeurobiologyConcentration-effect RelationshipsDrug DependenceDrug ToleranceDrugs Of AbuseDose ResponseDose-response FunctionsDrug ReinforcementFixed Ratio SchedulesIntravenous Self-administrationProgressive Ratio SchedulesRodent Environmental EnrichmentVariable Ratio Schedules