Auricular transcutaneous vagus nerve stimulation alters directed cortical communication during intentional actions

Understanding how intentional behavior emerges from neural dynamics requires linking cognitive theories with neurobiology. We combined auricular transcutaneous vagus nerve stimulation (atVNS) with EEG-based directed connectivity analyses to probe action-effect integration in a canonical theta-band network comprising the anterior temporal lobe (ATL), insular cortex (IC), and inferior frontal cortex (IFC). We show that this core network supports action-effect processing, but atVNS additionally recruited posterior temporal/ventral stream regions (PTL) and altered directed information transfer in the network. While some network properties (e.g., IFC-PTL asymmetry) were involved in both action-effect perception and planning, others (e.g., IC-IFC coupling) were specific to only one of these processes, suggesting that ideomotor theory would benefit from process-specific assumptions regarding the cortical dynamics. The results can be interpreted as reflecting enhanced GABAergic transmission underlying atVNS effects, providing further neurobiological foundation for ideomotor theory on the basis of directed cortical communication and neuromodulation.