In recent years, there has been a focused research interest to examine the event-related potential (ERP) components in gambling-type paradigms. This trend is a continuation of numerous studies on error-related negativity (ERN or Ne), a sharp negative deflection in the ERP waveform with a frontocentral scalp distribution peaking around 100 ms following an erroneous response in choice-reaction tasks [1-14]. Medial frontal negativity (MFN), a closely related phenomenon to ERN, was recently reported by Gehring & Willoughby [15]. MFN occurred around 250 ms after outcome stimuli that informed human participants about gains and losses in a two-choice two-outcome (TCTO) gambling task. While various researchers have referred to this component as feedback-related negativity (FRN) [16] or feedback ERN (fERN) [17], we propose that this component be labeled as outcome-related negativity (ORN) for the following reasons: 1) the term outcome in ORN correctly denotes the quality (loss/gain) and quantity (large/small) of the outcome event that has a reinforcement value, 2) the term error in ERN and fERN may only be attributable for error-related paradigms, 3) the term MFN indicates the brain area of
