Different relationships between central dopamine system and sub-processes of inhibition: Spontaneous eye blink rate relates with N2 but not P3 in a Go/Nogo task

Clinical studies show that dysfunction of the dopamine (DA) system could differently modulate N2 and P3 components in a Go/Nogo task, a classical inhibition task. However, results of previous clinical studies cannot be arbitrarily generalized to healthy adults. Thus, the present exploratory study aimed to investigate whether there are significant and variable relationships between individual differences of the DA system in normal healthy persons and N2- and P3-related sub-processes of inhibition in a Go/Nogo task. DA function was measured by spontaneous eye blink rate (EBR), which is an effective clinical and non-invasive measure and strongly related to the activity of the central dopaminergic system. A total of 28 young adults participated in this experiment. Results showed that Nogo-N2 and Nogo-P3 of all participants were larger than Go-N2 and Go-P3, while Nogo-N2 and Nogo-P3 were significantly related with Nogo-accuracy. Moreover, it was shown that higher EBRs were significantly correlated with larger and more negative N2 amplitudes under Go- and Nogo-conditions; however, there were no significant correlations between participants' EBRs and N2 latencies, and between EBRs and average amplitudes of P3 under the two conditions. Based on these results, we concluded that the central DA system was associated with the N2-related conflict monitoring rather than P3-related sub-process of inhibition.