title: Free-operant avoidance behavior and gastric ulceration in rats.
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D003216:Conditioning, Operant; D004195:Disease Models, Animal; D004597:Electroshock; D005260:Female; D006799:Housing, Animal; D006801:Humans; D051381:Rats; D012055:Reinforcement Schedule; D013276:Stomach Ulcer; D013315:Stress, Psychological