Behavioral and neurophysiological signatures of interoceptive enhancements following vagus nerve stimulation

Abstract

An accruing body of research has shown that interoception (the sensing of signals from the body's internal milieu) relies on both a direct route (afforded by the vagus nerve) and a secondary route (supported by somatosensory mechanisms). However, no study has causally tested the differential role of these pathways, let alone via direct stimulation. To bridge this gap, we tested whether multidimensional signatures of interoception are modulated by noninvasive vagus nerve stimulation (nVNS). Sixty‐three participants were divided into an nVNS and a sham‐stimulation group. Before and after stimulation, both groups performed a validated heartbeat detection (HBD) task including a genuinely interoceptive condition (monitoring one's own heartbeat) and a control exteroceptive condition (tracking an aurally presented heartbeat). Electroencephalographic signals were obtained during both conditions to examine modulations of the heartbeat‐evoked potential (HEP). Moreover, before and after stimulation, participants were asked to complete a somatosensory heartbeat localization task. Results from the interoceptive condition revealed that, after treatment, only the nVNS group exhibited improved performance and greater HEP modulations. No behavioral differences were found for the exteroceptive control condition, which was nonetheless associated with significant HEP modulations. Finally, no between‐group differences were observed regarding the localization of the heartbeat sensations or relevant cardiodynamic variables (heart rate and or heart rate variability). Taken together, these results constitute unprecedented evidence that the vagus nerve plays a direct role in neurovisceral integration during interoception. This finding can constrain mechanistic models of the domain while informing a promising transdiagnostic agenda for interoceptive impairments across neuropsychiatric conditions.

Auricular transcutaneous vagus nerve stimulation modulates the heart-evoked potential

“…Richter, et al (2020) used the GammaCore device (ElectroCore, LLC) to transcutaneously stimulate the cervical vagus nerve in a between-subjects design 81 . Substantial methodological differences make it difficult to directly compare the present results with Richter and colleagues' report.…”

Does Long-Term Training in a Water Immersion Environment Change Interoception?

“…Several short-duration WI protocols all increased HR variability (HRV), and the greatest impact of WI on HRV is on the high-frequency (HF) component, indicating a shift toward enhanced parasympathetic nervous activity [ 61 , 62 ]. A previous study using transcutaneous auricular vagus nerve stimulation (taVNS), which stimulates the vagus nerve noninvasively and inhibits sympathetic nervous activity, revealed that interoception significantly improved after this stimulation, although cardiac sympathetic nervous activity returned to baseline levels [ 63 ]. The authors explained that taNVS could activate the insular cortex, which modulates interoception.…”

Interoception Primes Emotional Processing: Multimodal Evidence from Neurodegeneration

“…For the tapping-priming phase, we used a validated heartbeat detection (HBD) task ( Canales-Johnson et al, 2015 ; García-Cordero et al, 2016 ; Yoris et al, 2017 , 2018 ; Salamone et al, 2018 , 2020 ; Abrevaya et al, 2020 ; Richter et al, 2021 ; Richter and Ibáñez, 2021 ). Participants were required to tap a computer keyboard along with their heartbeats (Intero) or external stimuli (Extero).…”