Peripheral bodily processes are conveyed to the brain via several mechanisms promoting psychological and behavioral adaptations. There is now a solid body of evidence indicating that both cardiac and respiratory activity influence central-nervous processes mediating perception and behavior. This symposium will cover recent research into such peripheral modulation of central-nervous processes from basic reflexes to higher order cognition and action control. André Schulz (Luxemburg) will present a series of studies demonstrating cardiac modulation of the startle reflex and how it may be employed to assess the integrity of cardioafferent traffic. Leon von Haugwitz (Dortmund) will present behavioral and EEG studies revealing that cardiac activity modulates different aspects of sensorimotor control relevant to conflict processing. Diving deeper into the neural correlates of motor control, Maria Herrojo-Ruiz (London) will provide evidence indicating that EEG alpha and beta suppression during motor imagery is influenced by the cardiac cycle. Cardiorespiratory activity may not only affect sensorimotor processes, but could also influence feelings of control that are associated with voluntary actions and their outcomes. Marta Gerosa (Berlin/Leipzig) will show how the coupling between cardiorespiratory rhythms and voluntary actions modulates this Sense of Agency. Beyond such acute effects, cardiorespiratory signals may even facilitate long-term behavioral adaptations. Miriam Nokia (Jyväskylä) will demonstrate how learning processes and their electrophysiological correlates are modulated along cardiac and respiratory cycles in studies employing eyeblink-conditioning with young and elderly samples. Together, these contributions illustrate how cardiorespiratory signals influence brain activity to change the way we perceive and interact with our environment.

Afferent signals from different visceral organs are integrated in behavior, cognition and emotion. There is no non-invasive method to directly assess visceral-afferent signals. Startle eye blink responsiveness, mediated by brainstem reflexes, can be modulated by cognitive processes. This study set demonstrates that startle eye blink responses can also be used as a method for an indirect assessment of visceral-afferent signals. First, startle responses to acoustic noise bursts were lower when presented in the early (R-wave +230 ms) than in the late cardiac cycle phase (R +530 ms), an effect that could only be observed in healthy individuals, but not in those with diabetic autonomic neuropathy. This effect is also reflected in self-reported intensity of, and electrocortical responses to startle stimuli. Hence, this effect relies on intact baro-afferent signal transmission. Second, the perturbation of afferent cardiac signals by acute stress changes the pattern of this so-called ‘cardiac modulation of startle’ (CMS), whereas exogenous cortisol administration had no effect. Therefore, the cardiodynamic changes associated with the autonomic stress response may be reflected in the CMS pattern. Third, stress-associated mental disorders, such as depersonalization disorder, showed altered CMS patterns, suggesting a dysfunctional processing of visceral-afferent signals in these samples. Finally, also respiratory phases and water ingestion elicited changes in startle eye blink responses, implying that afferent signals from the respiratory and gastrointestinal system may be assessed via this method, as well. In summary, visceral modulation of startle can be used to assess visceral-afferent signal transmission from different organs in health, stress, and disease.

Cardiac activity influences central-nervous processes modulating both perception and action. In two studies, we examined how cardioafferent traffic influences conflict processing, a mechanism responsible for resolving interference between automated and goal-directed responses. To explore modulatory pathways of these effects, participants underwent repeated Cold Pressor Tests (CPT) increasing stress-related cardiovascular load. In the first study, we found conflict-specific cardioafferent effects by contrasting sensorimotor and cognitive conflicts using an adapted Simon task. Accuracy improved for compatible but decreased for incompatible trials during systole versus diastole specifically for sensorimotor conflicts, indicating facilitated automated responses during systole. In our second study, we examined attentional conflicts by means of a change detection task where participants had to detect lateral luminance changes occasionally paired with more salient contralateral orientation changes. We found that for conflicts, systole trials showed increased errors but decreased misses, again pointing to more automated response tendencies. For unilateral luminance changes, systole trials showed more misses, accompanied by frontal alpha/beta lateralization indicating attentional contributions to these effects. Moreover, this effect depended on cardiovascular reaction patterns during the CPT. Overall, our findings point towards a facilitation of automated responses induced by the visual context of a stimulus during systole. However, there was no effect of cardioafferent traffic on the frontocentral N2 indicating that the behavioral effects are not driven by altered conflict processing. Rather, cardioafferent traffic seems to alter behavior under conflict via sensorimotor and attentional mechanisms, an influence that is sensitive to the cardiovascular effects of acute stress.

Despite growing evidence that cardiac afferent signalling modulates perception, cognition, and action, its translational potential—particularly for assistive technologies such as brain-computer interfaces (BCIs)—remains underexplored. In this talk, I present findings from two EEG studies examining how cardiac cycle phase influences motor processes relevant to BCI applications: motor imagery (MI) and motor preparation.

In the first study, we assessed alpha (8–12 Hz) and beta (13–30 Hz) suppression during MI and motor execution of thumb abductions, time-locked to systole or diastole. Imagined, but not executed, movements cued during diastole elicited significantly greater contralateral alpha and beta suppression, suggesting enhanced sensorimotor engagement to cues presented during phases of putatively low baroreceptor activity. EMG data showed increased muscle activation during diastole for both real and imagined movements, supporting a facilitatory effect of this cardiac phase. These results identify cardiac cycle–sensitive windows that may enhance MI-based BCIs.

The second study investigated cardiac modulation of volition in Libet’s task. We found that self-initiated movements in the W-condition—requiring participants to report the urge to move—clustered in diastole. Modulation of heart-evoked potentials did not explain the results, suggesting these timing effects are not driven by neural responses to heartbeats. We interpret this as evidence that cardiac input shapes motor preparation and contributes to the subjective experience of volition.

Together, these studies show that diastole facilitates both motor imagery and the timing of the ‘urge to move’, advancing our understanding of how visceral signals shape sensorimotor control and inform BCI development.

Sense of agency (SoA), the experience of controlling voluntary actions and their outcomes, is traditionally attributed to sensorimotor predictive processes. Recent frameworks propose that inner bodily signals, like cardiac and respiratory rhythms, contribute to action generation and self-attribution, with SoA emerging from integrated interoceptive-sensorimotor processes. Despite voluntary action initiation preferentially aligning with specific cardio-respiratory phases, the functional role of such cardio-respiratory phase biases in modulating SoA remains unclear.

In this preregistered study (osf.io/z7g9h), forty-four healthy adults (28.7±7.24 years; 23F) completed an intentional binding task alongside continuous cardiac and respiratory recordings. Action and tone binding measures were computed to conduct circular and binary analyses of cardio-respiratory activity. All analysis scripts will be shared as reproducible, open-access pipelines, developed through a collaborative initiative (“Brain-Body Analysis Special Interest Group”).

Behavioral results replicated classical intentional binding effects: voluntary actions were perceived later (32.87±63.54 ms) and tones earlier (-88.18±78.80 ms) when occurring in combination, compared to alone. Cardiac analysis showed a trend toward initiating keypresses early in the cardiac systole, with participants proportionally favoring systole over diastole for action generation. In binary analysis, cardiac phase at action or tone onset did not directly modulate action or tone binding, respectively. However, exploratory analysis showed that the more tones occurred during systole – a phase of high interoceptive noise – the weaker tone binding became.

While replicating cardiac phase biases in voluntary action initiation, these biases did not influence the subjective experience of agency. Ongoing respiratory analyses will further elucidate how inner bodily rhythms contribute to SoA.

We have been studying how the phases of respiration and the cardiac cycle affect brain responses and learning about external stimuli. Our findings indicate that hippocampus-dependent associative motor learning, specifically the classical conditioning of the eyeblink response, is enhanced in individuals who receive the conditioned stimulus consistently at diastole during expiration, compared to those trained at systole during inspiration. This effect is observed in both young and elderly adults. In conclusion, the state of the body and brain fluctuates at various frequencies, and these oscillations gate information processing. However, there is significant variation between individuals in how the body and brain connect and how this affects cognition. In the future, we are interested in researching the utility of personalized approaches in optimizing learning.