Stimulating the vagus nerve reduces susceptibility to body illusions, study finds

New research published in the journal Psychophysiology suggests that stimulating a nerve in the ear can make people less likely to feel that a fake hand is part of their body. This process, known as the rubber hand illusion, relies on the brain’s ability to integrate different types of sensory information. The study found that people who received gentle electrical stimulation to the vagus nerve were less susceptible to this illusion, indicating they were more in touch with signals from their real body. This discovery could eventually help improve treatments for mental health conditions where bodily awareness is disrupted.

The vagus nerve plays a key role in how the body communicates with the brain. It carries signals from the heart, lungs, and other organs, helping the brain keep track of the body’s internal state. Scientists have long been interested in this nerve because of its wide-reaching effects on emotion, attention, and self-awareness. In recent years, researchers have explored how stimulating this nerve might improve mental health or enhance certain brain functions.

A non-invasive method known as transcutaneous auricular vagus nerve stimulation, or taVNS, delivers mild electrical pulses to a part of the ear that connects to the vagus nerve. Past studies have shown that taVNS can improve a person’s ability to notice signals from inside the body, like their heartbeat. But researchers have not yet fully understood whether this stimulation can change how people experience their bodies more broadly—especially their sense of body ownership.

To explore this, a team of researchers asked whether taVNS could influence how people experience body ownership, using a high-tech version of the rubber hand illusion. In this illusion, a person sees a fake hand being touched in the same way and at the same time as their own hidden hand. Over time, many people begin to feel as though the fake hand is actually part of their body. This is a powerful demonstration of how the brain combines touch, sight, and body position to form a sense of physical self.

In this study, the researchers used virtual reality to recreate this illusion and included both visual-tactile feedback (a virtual brush stroking the hand) and visual-cardiac feedback (the hand flashing in time with the person’s heartbeat).

“I’ve always been fascinated by how our sense of self emerges from the interaction between our brain and body. Body ownership—our feeling that our body belongs to us—is an essential part of self-awareness, yet it can be surprisingly malleable,” explained study author Alisha Vabba, a postdoctoral researcher at the Italian Institute of Technology in the Neuroscience and Society Lab.

“Previous research suggested that interoception, or the ability to sense internal bodily signals like heartbeats, plays a role in body ownership. Since taVNS has been shown to enhance interoceptive awareness, I wanted to explore whether it could influence body ownership as well. Understanding this relationship has implications not only for neuroscience but also for clinical conditions where body awareness is disrupted.”

The study included 27 healthy young adults. Each participant visited the lab twice, once receiving real vagus nerve stimulation and once receiving sham stimulation. The sessions were at least a week apart and the order was randomized. During the stimulation, electrodes were placed on the ear—either on a region connected to the vagus nerve (for real stimulation) or on the earlobe, which is not connected to the nerve (for sham).

The researchers made sure the level of stimulation was noticeable but not uncomfortable. During both sessions, participants completed a series of tasks in virtual reality designed to trigger the rubber hand illusion. In some trials, the feedback was synchronous—meaning the visual cues matched the person’s heartbeat or the timing of the touch. In other trials, the feedback was asynchronous.

To measure how strongly participants experienced the illusion, the researchers used both objective and subjective measures. One was proprioceptive drift—the extent to which participants misjudged the location of their real hand, shifting toward the virtual hand. The other was a set of questions asking how strongly they felt the virtual hand belonged to them. The researchers also collected physiological data, including heart rate, heart rate variability, and skin-based nerve activity, to see how the body responded to the stimulation.

During sham stimulation, the researchers found that participants were more likely to experience the illusion when the visual and touch or heartbeat feedback was synchronized. This is consistent with earlier studies.

But during real vagus nerve stimulation, this effect disappeared. There was no difference between synchronous and asynchronous trials, suggesting that taVNS disrupted the illusion. People became less likely to feel that the fake hand was their own, regardless of whether the feedback was matched or not. This pattern was found in both the tactile and cardiac trials.

“I wasn’t hugely surprised but it was interesting to note the effect we expected was observed similarly for cardiac and tactile trials,” Vabba told PsyPost. “I expected to see a strong effect in the cardiac trials, as taVNS has been shown to improve interoception, making individuals more attuned to their internal bodily signals. However we saw an effect in both cardiac and tactile trials, suggesting that taVNS doesn’t just enhance cardiac awareness but plays a more general role in altering multisensory integration—affecting not only interoception but also how the brain processes and combines visual, tactile, and proprioceptive signals.”

The researchers also found that heart rate dropped slightly during active stimulation but not during sham, suggesting that the vagus nerve stimulation influenced the body’s arousal levels. However, other physiological measures, such as variability in heart rate and skin-based nerve activity, did not show strong or consistent changes. In fact, both real and sham stimulation appeared to raise skin nerve activity, possibly because any electrical stimulation—even if not targeting the vagus nerve—can cause a mild arousal response.

Importantly, the study did not find that a person’s baseline ability to sense their own heartbeat predicted how strongly they experienced the illusion. This is worth noting because previous studies had suggested that people who are more in tune with their internal signals may be less susceptible to body illusions. Here, that link did not hold up.

“Our study shows that the vagus nerve plays a crucial role in how we integrate different sensory signals from our body,” Vabba explained. “Normally, we combine visual, tactile, and proprioceptive information to create a sense of body ownership. When we applied taVNS, it altered this process—reducing susceptibility to the rubber hand illusion. This suggests that vagus nerve stimulation can shift the balance between external sensory input and internal bodily signals, making people rely more on their real body rather than external cues. This finding could have implications for understanding disorders where body perception is disrupted, such as depersonalization, certain anxiety disorders, and even chronic pain conditions.”

But as with all research, there are caveats to consider. “While our study provides interesting evidence for the role of vagus nerve stimulation in body ownership, it was conducted in a relatively small sample of healthy participants,” Vabba noted. “The effects of taVNS may vary between individuals, and it’s unclear how long-lasting these changes are. Additionally, while we used a well-established sham control, some physiological responses (like changes in skin sympathetic nervous activity) were observed in both real and sham stimulation, suggesting that non-specific effects of electrical stimulation might also play a role.”

Future studies should include a larger and more diverse group of participants and could add a no-stimulation control group to further separate the effects of the stimulation itself from the context of the experiment. In the long run, the researchers hope this work will lead to better understanding and potential therapies for disorders where the sense of bodily self is disturbed.

“A long-term goal for this line of research should be to explore how vagus nerve stimulation could be used to enhance body awareness and improve mental health conditions where interoception and self-perception are disrupted,” Vabba explained. “Disorders such as anxiety, PTSD, eating disorders, and depersonalization involve altered interoception, and if taVNS can strengthen body ownership and interoceptive accuracy, it may have therapeutic potential.”

The study, “The Vagus Nerve as a Gateway to Body Ownership: taVNS Reduces Susceptibility to a Virtual Version of the Cardiac and Tactile Rubber Hand Illusion,” was authored by Alisha Vabba, Keisuke Suzuki, Milica Doric, Tim J. Möller, Sarah Garfinkel, and Hugo Critchley.