Feedback related brain activity in a gambling task: a temporal analysis of EEG correlates

The pattern of neural correlates of feedback processing has been the subject of a number of studies, using both neuroimaging and electrophysiological recordings. A complex functional network was found to be activated after a choice in order to process a feedback and sustain an adaptive behavior. However, many aspects of this network are still unclear and further research is needed to better understand this process. We conducted an EEG study using a simple gambling task. Twenty three subjects participated to the study. We analyzed both EEG power spectrum and ERP components evoked by presentation of a feedback signal (money gain or loss) during a simple gambling task. Our data confirmed that a negative ERP component is present about 270 ms after feedback, particularly relevant following a choice with negative outcome. Furthermore, the theta and delta oscillatory activity seem to be correlated to a dynamic decision-making process within specific cortical networks. In particular, theta activity showed a valence dependent development between 150 and 350 ms post-feedback onset. Differently from previous studies (Cohen, Elger & Ranganath, 2007; Marco-Pallares, Cucurell, Cunillera et al., 2008), we did not find any valence effect in beta range. However, our data are consistent with Christie and Tata (2009), probably due to the nature of the gambling task used in both studies. In conclusion, our data, in line with some prior findings showed that the feedback related response is correlated to a complex pattern of cortical activation probably mediated by theta and delta activity.