as well as for the gain condition (gain 10¢ + gain 50¢) in order to have more trials per subject and more subjects per group. Mean trial numbers across the risk groups in each condition are: LR = 39.12 and HR = 36.51 for the loss condition; LR = 42.24 and HR = 40.53 for the gain condition. Although signal-to-noise-ratio (SNR) and minimum number of trials needed for the stability P3 in gambling paradigm have not been determined in the current study, trial numbers for each condition seem to be adequate. In view of the findings that the SNR did not differ when the trial numbers exceeded eight for the ERN/Pe components (Olvet and Hajcak, 2009), and that the components can be reliably measured with 8 trials for ERN (Olvet and Hajcak, 2009) and with 20 trials for the FRN (Marco-Pallares et al., 2011), it is very unlikely that SNR-related issues may confound the results of the current study given the higher number of trials in each condition.
