Apart from ORN, the P3 component of the ERP has also been studied to analyze whether this positivity is sensitive to valence (loss/gain) and amount (small or large). As previously discussed, we propose to term this positivity as Outcome-related Positivity (ORP). ORP can be defined as a large positivity occurring between 275-700 ms in response to outcome stimuli usually presented in gambling tasks. Very few studies have examined the ORP and ORN together. Yeung & Sanfey [22] reported that the ORP was sensitive to reward amount but insensitive to reward valence (with the ORN showing the opposite pattern), apart from the finding that the ORP (but not the ORN) showed sensitivity to the reward value of alternative outcomes. Apart from the finding that the peak-to-peak ORN amplitude of loss and neutral conditions were significantly larger than that of win conditions, Toyomaki & Murohashi [28] reported two important observations on ORP to imply that ORP was sensitive to both the quality (loss/gain) and quantity (larger/smaller) of the bet: 1) The ORP peak amplitudes of win conditions were larger than those of
