title: Tobacco smoking and a 'stimulus barrier'.
mesh_terms: D000328:Adult; D003214:Conditioning, Classical; D004569:Electroencephalography; D005712:Galvanic Skin Response; D006185:Habituation, Psychophysiologic; D006339:Heart Rate; D006801:Humans; D008297:Male; D009949:Orientation; D010919:Placebos; D010947:Plants, Toxic; D012907:Smoking; D014026:Nicotiana
chemical_list: D010919:Placebos