Modulation of response inhibition with event-related atVNS showed EEG but no behavioral effects.

Response inhibition can be explained within the theory of event coding. Event file binding and reconfiguration have previously been studied in relation to various neurotransmitters. We aimed to activate the noradrenergic system through auricular transcutaneous vagus nerve stimulation (atVNS) to study effects on response inhibition. Forty healthy participants completed a Go/Nogo task under verum and sham phasic event-related atVNS stimulation with concomitant EEG measurement. The Go/Nogo task was designed to assess response inhibition with feature overlap between Go and Nogo trials requiring reconfiguration of event files. In overlapping Go trials, reaction times increased, and accuracy decreased compared to non-overlapping trials. False alarm rates were higher in overlapping Nogo trials. There were no influences of atVNS on behavioral data. Using multivariate pattern analysis, EEG data showed sustained and robust differences in classification between verum and sham stimulation across trial types. Off-diagonal activity was consistently observed in time generalization matrices between 100 and 900ms for overlapping Go and Nogo conditions, as well as for non-overlapping Go conditions and until approximately 750ms for non-overlapping Nogo conditions. There were no trial-specific effects of phasic atVNS, it affected all trials in the verum condition. In conclusion, this study demonstrates that short-lasting, event-related atVNS has an effect on EEG activities, but not on behavioral outcomes during a Go/Nogo task that requires event-file reconfiguration. As EEG changes were detected also in non-stimulated trials, there may be effects of the short-duration atVNS outlasting the period of stimulation.