Interoception, the processing and perception of signals from inside the body, affects how we experience and regulate social situations. For example, accurate interoception enhances the regulation of negative emotions caused by social exclusion. Understanding the mechanisms underlying the impact of interoception on social interaction is essential, as their negative facets, such as social stress, social isolation, and loneliness are fundamental risk factors for mental disorders. First, we delineate how social stress and isolation are associated with interoception, with an emphasis on both physiological stress axes. André Schulz (Luxembourg) will present two studies on the impact of acute and chronic stress on interoception. Thereafter, Aleksandra Piejka (Leipzig) will show how loneliness is related to interpersonal distance and peripersonal space during social situations in virtual reality settings. Then, Miriam Kipping (Ulm) will address how social stress effects on gastric interoception shapes eating behavior. Second, we introduce three interventions to modify interoception. In two studies, Lisa Lai (Luxembourg) investigated the impact of transcranial magnetic stimulation (TMS) on the interoceptive brain network and social stress responsiveness. Finally, Carlos Ventura-Bolt (Potsdam) will address how transcutaneous auricular vagus nerve stimulation (taVNS) and heart rate variability (HRV) biofeedback affect interoception and physiological stress axis activation. Our findings suggest a bi-directional effect between interoception and social stress/isolation in that stress may reduce interoception, but high interoception also helps to regulate the negative impact of social stress/isolation. TMS, taVNS, and HRV biofeedback were demonstrated as three intervention procedures that enhance interoception and, thereby, overcome negative consequences of social stress/isolation.

Ascending and descending signals between the brain and the body are inherently connected. Interoception, the processing of signals from inside the body, is an example of ascending signal transmission, whereas stress is associated with descending signal transmission. Accordingly, first studies indicate that acute and chronic stress affects cardiac interoceptive accuracy (IAc). However, the impact of stress on other facets of interoception (interoceptive attention/IAt) remained unclear. Therefore, we investigated the impact of acute and chronic stress on cardiac IAc (heartbeat perception) and IAt (heartbeat-evoked potentials/HEPs). In Study 1, healthy individuals (N=66) underwent heartbeat counting tasks (HCTs) and distraction tasks (DTs) before and after a socially-evaluated cold pressor test (SECPT) vs. a control task, while HEPs were assessed. In Study 2, chronically-stressed schoolteachers (N=68) completed HCTs and DTs before and after an SECPT. Questionnaires and hair cortisol/dehydroepiandosterone (DHEA) served as measures of chronic stress. In healthy individuals, acute stress enhanced IAt (HEPs), but did not affect IAt (HCT). In contrast, chronically-stressed individuals showed a decrease of IAt (HEPs) after acute stress. They also reported fewer guessing strategies in the HCT after stress, whereas IAc was unchanged. Self-reported chronic stress was negatively associated with IAt, while hair cortisol/DHEA ratio negatively correlated with cardiac IAc. Hence, acute stress may increase IAt in a healthy state, which may turn into the opposite in states of chronic stress. IAc seems to be unaffected by stress, except for reporting strategies. These changes in interoception induced by stress may account for somatic symptom generation in stress-related diseases.

Loneliness, a perceived lack of social connectedness and support, has been recognized as a critical public health concern with significant implications for individual well-being. Extensive research has established loneliness as a major risk factor for various adverse health outcomes, including psychiatric disorders, cardiovascular disease, and all-cause mortality. Theoretical frameworks propose that the detrimental effects of loneliness on mental and physical health are fundamentally linked to two primary mechanisms: disrupted physiological responses to social stimuli and pervasive negative cognitive biases.

Previous investigations have suggested that loneliness is associated with compromised integration of interoceptive trust signals in social situations, indicating a complex psychophysiological underpinning of social disconnection. Studies conducted by my research team has empirically demonstrated that experimental induction of loneliness can significantly decrease adaptive parasympathetic response, as measured by changes in heart rate variability (HRV) levels during social processing tasks. Moreover, we found that higher levels of loneliness are correlated with lower resting-state HRV in male participants.

Currently, my research focuses on establishing comprehensive links between resting, task-related, and real-world HRV measurements and neuropsychological post-COVID symptoms within the broader context of loneliness. Additionally, I am developing a research protocol to investigate how loneliness relates to interpersonal distance and peripersonal space dynamics during social interactions, utilizing immersive virtual reality settings to examine both behavioral and physiological responses at multiple levels of analysis.

The connection between eating behavior and both physical and mental health highlights the need to understand how eating behavior is regulated. Stress plays a significant role in shaping eating behavior, although its impact varies among individuals. To investigate the underlying mechanisms, we explored how acute stress influences gastric interoception – the ability to perceive stomach signals – alongside eating patterns and emotion regulation skills.

A total of 94 sober adults participated in the study, completing both a stress-inducing task and a control task in separate laboratory sessions. Thereafter, gastric interoceptive sensitivity was measured with a new method – the Magic Table (MT). This consists of the consumption of yogurt from a self-refilling bowl until perceiving satiation and fullness. Additionally, a subset of participants underwent the Two-step Water Load Test (WLT-II), a well-established measure of gastric interoceptive sensitivity, in two additional laboratory sessions.

The strong correlations between the gastric interoception indexes of the MT and the WLT-II support the MT’s validity. Stress did not significantly change gastric interoceptive sensitivity. Nevertheless, participants with high but not low levels of emotion regulation difficulties, dietary restraint, and uncontrolled eating displayed reduced fullness sensitivity under stress compared to the control condition.

These findings emphasize the role of gastric interoception in stress-related eating behaviors and highlight the necessity of interventions focusing on this mechanism for a subgroup of individuals at risk for dysregulated eating under stress. The implications will be discussed in the context of interoception-focused interventions, such as vagus nerve stimulation.

Interoception plays a crucial role in emotional regulation, stress responses, and overall well-being. Despite growing interest in interoceptive processes, their neural mechanisms and plasticity remain insufficiently understood, especially regarding their modulation by brain stimulation and acute stress. This project investigates interoceptive plasticity by examining how Theta Burst Stimulation (TBS) and stress influence interoceptive accuracy (IAc) and interoceptive attention (IAt), two distinct aspects of interoception. IAc reflects the objective ability to perceive bodily signals, while IAt is assessed through the amplitude of heartbeat-evoked potentials (HEPs), which represent neural responses to cardiac signals at different time intervals.

Two experimental studies were conducted. The first examined the effects of three TBS protocols—intermittent (iTBS), continuous (cTBS), and intermediate (imTBS)—on IAc and IAt. Results showed that iTBS selectively enhanced IAt, as indicated by an increased HEPs interval, without affecting IAc, suggesting distinct neural mechanisms for these interoceptive dimensions. The second study investigated the impact of acute stress, induced by the Socially Evaluated Cold Pressor Task (SECPT), on interoception and whether TBS protocols influenced stress responsiveness. Acute stress was found to increase IAt (higher HEP amplitudes) but did not improve IAc, further supporting the dissociation between interoceptive attention and accuracy. A trend toward increased negativity of late HEPs was observed following cTBS.

These findings highlight the dynamic nature of interoceptive plasticity, demonstrating that interoceptive processes can be selectively modulated by neuromodulation and stress, and underscore the potential of brain stimulation as a therapeutic approach.

As interoceptive disfunctions have been proposed as vulnerability factors for psychopathological symptoms, there has been emerging interest in developing interventions to enhance interoceptive processing. This talk will present findings from two studies exploring the potential of cost-effective (neuro)modulation techniques—transcutaneous auricular vagus nerve stimulation (taVNS) and heart rate variability biofeedback (HRVBFB)— as methods to improve cardiac interoception. In the first study (N=53), we investigated the effects of taVNS on cardiac interoceptive accuracy and heart-evoked potentials (HEPs), using a within-subject, crossover design (taVNS vs. sham). Results showed that taVNS helped preserve interoceptive accuracy levels over time and elicited larger HEP amplitudes. We also found during taVNS, that HEP amplitudes mediated the positive relationship between interoceptive accuracy and HRV, a correlate of physiological adaptability. These findings suggest that taVNS may enhance cardiac signaling, thereby improving physiological regulation. The second study tested the effects of a HRVBFB on cardiac interoception, using a between-subject design. Preliminary data (N=45) confirmed the expected increase in HRV following HRVBFB. Mediation analysis further revealed that improvements in cardiac interoception were mediated by HRV increases, suggesting that enhanced physiological adaptability may support interoceptive processes. The final results (N=74) will be presented at the symposium. Together, these studies provide new insights into how interoceptive processing can be enhanced, offering potential pathways to improve mental health.