A) Mean late positive potentials (LPPs) from centro-parietal sensors (see inset for electrode locations) evoked before smoking-cessation treatment by unpleasant, neutral, pleasant, and cigarette-related stimuli in smokers assigned to clusters 1 and 2. B) Mean LPPs from centro-parietal sensors evoked by the different semantic contents in smokers assigned to clusters 1 and 2. Unpleasant contents: mutilations (MUT; high emotional arousal), sad (SAD; low emotional arousal; e.g., grief, disease), and objects (UNPo; e.g., pollution, accidents). Pleasant contents: erotic couples (ERO; high emotional arousal), romantic couples (ROM; low emotional arousal), and objects (PLEo; e.g., food, landscapes). Neutral contents: people (NEUp) and objects (NEUo; e.g., household objects). Cigarette-related contents: people smoking (CIGp) and cigarette-related objects (CIGo; e.g., ashtrays, cigarettes). Note: *** = p < 0.00001, ** = p < 0.05, * = p < 0.10. All p levels are corrected for multiple comparisons.