Auricular Transcutaneous Vagus Nerve Stimulation Diminishes Alpha-Band–Related Inhibitory Gating Processes During Conflict Monitoring in Frontal Cortices

Abstract

Background Pursuing goals is compromised when being confronted with interfering information. In such situations conflict monitoring is important. Theoretical considerations on the neurobiology of response selection and control suggest that auricular transcutaneous vagus nerve stimulation (atVNS) should modulate conflict monitoring. However, the neurophysiological-functional neuroanatomical underpinnings are still not understood. Methods AtVNS was applied in a randomized crossover study design (N=45). During atVNS or sham stimulation, conflict monitoring was assessed using a Flanker task. EEG data were recorded and analyzed with focus on theta and alpha band activity. Beamforming was applied to examine functional neuroanatomical correlates of atVNS-induced EEG modulations. Moreover, temporal EEG signal decomposition was applied to examine different coding level in alpha and theta band activity. Results AtVNS compromised conflict monitoring processes, when atVNS was applied at the second appointment in the crossover study design. On a neurophysiological level, atVNS exerted specific effects since only alpha-band activity was modulated. Alpha-band activity was lower in middle and superior prefrontal regions during atVNS stimulation and thus lower when there was also a decline in task performance. The same direction of alpha-band modulations was evident in fractions of the alpha-band activity coding stimulus-related processes, stimulus-response translation processes, and motor response-related processes. Conclusions The combination of prior task experience and atVNS compromises conflict monitoring processes. This is likely due to reduction of alpha-band associated inhibitory gating process on interfering information in frontal cortices. Future research shall pay considerable attention to boundary conditions affecting the direction of atVNS effects.

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

“…Moreover, alpha oscillations have been linked to mechanisms underlying IC, such as the suppression of irrelevant or interfering information ( Vaden et al, 2012 ). Our findings also support work showing a stronger power of frontal and central alpha oscillations when performance in inhibition tasks increases, via top-down inhibitory strategic processes ( Hwang et al, 2016 ; Konjusha et al, 2022 ). Additionally, our findings on the change in alpha oscillations support reports that tVNS can activate endogenous neuromodulatory signaling, such as LC-NE activity, which is correlated with increased arousal ( Sharon et al, 2021 ); this, in turn, improves the ability to overcome the interfering effects of irrelevant information in the prefrontal cortices.…”

“…Several studies have proposed that there exists an alpha-associated inhibitory gating process for interfering information in the frontal cortices. An increase in alpha activity may reflect inhibitory gating processes, whereby increased alpha power-blocking oscillation activity could block interfering or irrelevant signals to improve information processing efficiency and strengthen the dynamic functional responsiveness of brain networks ( Konjusha et al, 2022 ). In cognitive control paradigms such as the SST or the go/no-go task, response inhibition after a stop signal or no-go stimulus has been associated with increased alpha power ( Schmiedt-Fehr et al, 2016 ).…”

Electroencephalographic Patterns in taVNS: A Systematic Review

“…On the other hand, 12 studies measured the ERPs induced by taVNS using different types of tasks. The most common activity used to detect the ERPs was the Oddball task [ 40 , 42 , 43 ], and cognitive conflict resolution tasks [ 28 , 31 , 32 , 36 ].…”

Short-term transcutaneous vagus nerve stimulation increases pupil size but does not affect EEG alpha power: a replication

“…Ricci et al [48] found no effect of long-term taVNS on alpha power, also with a limited sample size (n=8). To further complicate matters, Konjusha et al [49] reported that long-term taVNS in healthy participants modulated alpha power, but in a location-dependent manner: taVNS increased alpha activity over superior parietal regions, but attenuated alpha over middle and superior frontal regions. Finally, Chen et al [50] found that long-term taVNS attenuated alpha power, but only in the higher alpha-frequency range (~11 Hz) and in an eyes-closed (but not eyes-open) condition.…”