Neural signatures of reactive and intentional inhibitions: An ERP study

Abstract

Humans can inhibit an action based on external instruction (i.e., reactive inhibition) or internal decision (i.e., intentional inhibition). Although some functional magnetic resonance imaging (fMRI) studies have documented the relationship between reactive and intentional inhibitions, they could not provide pertinent temporal dynamics information due to fMRI’s low temporal resolution. Therefore, in the current study, we explored this issue by extracting the time-domain dynamics and oscillatory-power dynamics from electroencephalographic (EEG) data while participants performed a modified Go/NoGo/Choose task, in which free choices trials were integrated with conventional go/nogo trials. Participants were asked to decide for themselves to either inhibit or execute an action for free choices trials, and to respond properly according to go/nogo signal for conventional go/nogo trials. Two important results were obtained. First, for the reactive condition, nogo trials elicited greater N2 and P3 amplitudes and induced more pronounced delta, theta, and beta band oscillations than go trials, while for the intentional condition, nogo trials only elicited greater P3 amplitudes and triggered pronounced beta band oscillations compared to go trials. Second, while the P3/delta, theta, and beta oscillations were larger for reactive nogo trials than for intentional go/nogo trials, the P3/delta and theta oscillations were larger for intentional go/nogo trials than for reactive go trials. Together, these results suggest that there are both similarities and differences in oscillatory dynamics between reactive and intentional inhibitions. This study is the first to investigate the relationship between reactive and intentional inhibitions at the time-frequency domain, and the current results expand our understanding about different inhibitions.