Training and Transfer Effects of Combining Inhibitory Control Training With Transcutaneous Vagus Nerve Stimulation in Healthy Adults

Abstract

Inhibitory control training (ICT) is a promising method to improve individual performance of inhibitory control (IC). Recent studies have suggested transcutaneous vagus nerve stimulation (tVNS) as a novel approach to affect cognitive function owing to its ability to modulate the locus coeruleus-noradrenaline system. To examine the synergistic effects of combining ICT with tVNS, 58 young males in college were randomly assigned to four groups: ICT + tVNS, ICT + sham tVNS, sham ICT + tVNS, and sham ICT + sham tVNS. Participants were instructed to complete three sessions that comprised pre-training tests, a training session, and post-training tests sequentially. Results showed that the ICT + tVNS group significantly improved training and near-transfer effects on the stop-signal and Go/No-go tasks, and these effects were larger than those of the other groups. However, none of the groups exhibited the far-transfer effect on the color-word Stroop task. These results suggest that tVNS augments the intervention effects of training and similar inhibition tasks to achieve the synergistic effect; however, it does not modulate the effects of non-training tasks and obtain the far-transfer effect. ICT combined with tVNS may be a valuable intervention for improving IC in healthy individuals in certain industries and offers novel research ideas for using tVNS for cognitive improvement.

Synergistic effects of transcutaneous vagus nerve stimulation and inhibitory control training on electrophysiological performance in healthy adults

“…Interestingly, we found no significant difference in signal-N2 amplitude between pre-and post-tests in the tVNS + ICT intervention group. In line with our previous results, where we found that p (respond| signal) in the SST did not differ significantly between the pre-and post-tests with tVNS + ICT intervention (Wang et al, 2022), the present finding on signal-N2 amplitude seems to demonstrate that N2 amplitude could be a marker with which to assess the ability of processing conflict signals monitored in IC. Additionally, the ceiling effect of response inhibition (Bürki et al, 2014) in the SST might be the main reason why there were no significant behavioral [p (respond| signal) ] or electrophysiological (signal-N2 amplitude) performance changes indicative of IC enhancement in the tVNS + ICT group.…”

“…This finding is consistent with those of previous studies on IC practice manifesting the frontal N2 latency modulation on the temporal dynamics (Millner et al, 2012), and subjects exhibited faster N2 latency after inhibition training (Schroder et al, 2020). In addition, our findings on the signal-N2 latency in the frontal region are in line with the effects of ICT on behavioral performance, whereby subjects who have undergone ICT obtained a faster stop-signal reaction time (Wang et al, 2022).…”

“…Given the different neurological mechanisms underlying the effects of tVNS and ICT on IC enhancement, our group developed a novel intervention approach involving tVNS combined with ICT. In a recent behavioral study, we revealed that this approach can cause a training effect and transfer effect and achieve IC enhancement in healthy individuals ( Wang et al, 2022 ). However, the behavioral indicator of IC was not sufficient to evaluate the efficacy of the combined tVNS + ICT intervention, as participants were instructed not to produce a behavioral response to some types of stimuli.…”

“…Therefore, the aim of the present study was to investigate changes in neural activity in distinct brain regions following tVNS combined with ICT, including the time domain of ERP (signal-N2) and the frequency domain of EROs (alpha power), which reflect IC performance. We have previously demonstrated that this novel approach of tVNS combined with ICT can improve IC using behavioral analysis ( Wang et al, 2022 ). Here, to further evaluate the synergistic effect of tVNS combined with ICT, we extend this investigation to neurophysiological performance.…”

Transcutaneous Vagus Nerve Stimulation (tVNS) applications in cognitive aging: a review and commentary

“…In the domain of executive functions, the impact of tVNS stimulation has yielded mixed results. Studying cognitive control, many studies in this domain used a combination of behavioral and biomarker or EEG recordings to determine the effect of tVNS on cognition ( Fischer et al, 2018 ; Borges et al, 2020 ; Keute et al, 2020 ; Pihlaja et al, 2020 ; Tona et al, 2020 ; Konjusha et al, 2022 ; Wang C. et al, 2022 ). Some studies found that tVNS has a positive impact on executive functions, specifically on conflict-triggered adjustment of cognitive control and executive control of action, in both behavioral and EEG data ( Fischer et al, 2018 ; Keute et al, 2020 ).…”