Transauricular vagus nerve stimulation (taVNS) is increasingly spreading both in research and clinical practice; however, literature often presents non-uniform results in various cognitive domains. We propose a procedure based on the use of taVNS to investigate its effect on executive functions, also considering the modulation of the homeostatic balance between the sympathetic and parasympathetic systems. 40 (22F) volunteers participated in two separate sessions (stimulation/sham). After baseline measurements (heart rate variability) and a preliminary stimulation phase, they performed Stroop and go/no go tasks. Throughout the procedure, cardiac activity was recorded to obtain HRV parameters in different experimental conditions. Although performance differences were not identified in the tasks, the modulation of HRV parameters during the tasks indicates how taVNS can influence the balance between the sympathetic and parasympathetic systems during the execution of cognitive tasks. This effect is likely attributed to the taVNS acting on vagal tone, supporting the parasympathetic component.

Non-invasive vagus nerve stimulation has proven effective in modulating parasympathetic autonomic nervous system activity and various cognitive functions. This study investigated the effects of transauricular vagus nerve stimulation (taVNS) on body ownership and interoception in healthy subjects using a within-subjects experimental design (active taVNS/sham). The rubber hand illusion (RHI) and the Heartbeat Counting Task (HCT) were employed. Cardiac activity was recorded throughout the procedure to measure physiological indices of heart rate (HR) and heart rate variability (HRV). Ownership for the fake hand was observed in both active and sham stimulation, as indicated by drift and scores on illusion-relevant items (Q1-Q3). HR and HRV showed no variations between synchronous/asynchronous RHI or between stimulation conditions. Active taVNS resulted in decreased interoceptive meta-awareness. Individuals with lower interoceptive abilities exhibited heightened susceptibility to RHI during active taVNS, possibly due to perturbation of interoceptive signals and increased reliance on exteroceptive signals in constructing body representation.

It has been highlighted that non-invasive stimulation of the auricular branch of the vagus nerve (taVNS) have a neuromodulatory effects on several cognitive functions. In-fact, tha vagal system is central for the organism's homeostatic regulation and it has widespread connections with various cortical and subcortical areas. Hence, our focus on studying the impact of this technique on a multifaceted cognitive process essential in human experience, time perception. Healthy subjects underwent explicit (duration discrimination) and implicit (prediction) temporal tasks during two distinct experimental sessions of stimulation with taVNS: a sham condition (offline stimulator) and an active stimulation condition. Participants' cardiac activity (Heart rate variability) was monitored throughout the experiment. Preliminary results show improved performance during the active stimulation condition, particularly for predictive temporal tasks. TaVNS may enhance brain activity in areas crucial for implicit timing (e.g. upper temporal cortex, lower parietal cortex) and supporting the adjustment process of temporal prediction errors.