MethadoneHeroin DependenceNarcoticsOpiate Substitution TreatmentOpioid-Related DisordersBuprenorphineAnalgesics, OpioidMethadyl AcetateBrain ChemistryNeonatal Abstinence SyndromeBrain InjuriesMorphine DerivativesHeroinBrain NeoplasmsDrug OverdoseSubstance Abuse DetectionStreet DrugsBrain MappingSubstance Abuse, IntravenousCocaine-Related DisordersSubstance Withdrawal SyndromeMorphineSelf AdministrationSubstance-Related DisordersCodeineBrainNaloxoneCocaineNaltrexonePyrrolidinesReceptors, Opioid, muBrain EdemaBehavior, AddictiveDose-Response Relationship, DrugDrug and Narcotic ControlBrain StemBrain IschemiaNarcotic AntagonistsDextropropoxypheneMagnetic Resonance ImagingCrimeDrug InteractionsDrug UsersGas Chromatography-Mass SpectrometryTherapeutic CommunityPrisonersTime FactorsOpiumBrain AbscessPupilHarm ReductionStereoisomerismOxidoreductases, N-DemethylatingRats, Sprague-DawleyBehavior, AnimalBaltimoreMeconiumDirectly Observed TherapyHydromorphoneNew York CityNeuronsConditioning, OperantHypoxia, BrainPainBlood-Brain BarrierAnalysis of VarianceCerebral Cortex