FearConditioning, ClassicalFreezing Reaction, CatalepticConditioning (Psychology)AmygdalaExtinction, PsychologicalElectroshockMemoryGalvanic Skin ResponseStartle ReactionAvoidance LearningAssociation LearningBehavior, AnimalPhobic DisordersAnxietyAcoustic StimulationCuesDental AnxietyRats, Long-EvansAnalysis of VarianceEmotionsLearningCycloserineTime FactorsFacial ExpressionHippocampusDesensitization, PsychologicQuestionnaires