Dr Ruben Azevedo

Article

• Villani, V., Tsakiris, M., & Azevedo, R. (2019). Transcutaneous Vagus Nerve Stimulation Improves Interoceptive Accuracy. Neuropsychologia, 134. doi:10.1016/j.neuropsychologia.2019.107201
  Abstract View in KAR
  How can interoceptive accuracy, i.e. the objective ability to identify interoceptive signals, be improved? In the present study, we investigated whether non-invasive stimulation of the auricular branch of the vagus nerve (taVNS) modulates cardiac interoceptive accuracy, interoceptive sensibility, i.e. confidence in the identification of bodily signals, and interoceptive awareness, i.e. the capacity to evaluate one's ability in the objective task. Using a single-blind within-subjects design we compared participants' performance on the heartbeat counting task and on the heartbeat discrimination task during active and sham taVNS stimulation. Results revealed improved accuracy during active taVNS on the heartbeat discrimination task but not on the heartbeat counting task. Participants were also more confident during active stimulation, but interoceptive awareness was not modulated by taVNS. These findings show that taVNS can modulate interoceptive processing and suggest its potential as a tool to investigate body-brain interactions.
• Ambrosini, E., Finotti, G., Azevedo, R., Tsakiris, M., & Ferri, F. (2019). Seeing myself through my heart: Cortical processing of a single heartbeat speeds up self-face recognition. Biological Psychology, 144, 64-73. doi:10.1016/j.biopsycho.2019.03.006
  Abstract View in KAR
  Recent research has highlighted the contribution of interoceptive signals to different aspects of bodily self-consciousness (BSC) by means of the cardio-visual stimulation - i.e. perceiving a pulsing stimulus in synchrony with one’s own heart. Here, for the first time, we investigate the effects of individual heartbeats on a critical feature of BSC, namely the recognition of one’s own face. Across two studies, we explored the cardiac-timing effects on a classic self-face recognition task. In Study 1, participants saw morphed faces that contained different percentages of the self-face and that of another unfamiliar individual. Study 2 used a similar design, albeit participants saw morphed faces of the self-face and that of a familiar other to provide a better control of self-familiarity. Results from both studies consistently revealed that the cortical processing of cardiac afferent signals conveyed by the firing of arterial baroreceptors affects the speed, but not the accuracy, of self-face recognition, when a single picture is presented during cardiac systole, as compared to diastole. This effect is stronger and more stable for stimuli with more self-cues than other-cues and for ‘ambiguous’ stimuli – i.e. at the individual point of subjective equality. Results from Study 2 also revealed that cardiac effects on the speed of self-face recognition cannot be explained simply on the basis of the imbalanced familiarity between the self’s and other’s faces used. The present findings highlight the interoceptive contributions to self-recognition and may be expand our understanding of pathological disturbances of self-experience.
• Azevedo, R., Badoud, D., & Tsakiris, M. (2018). Afferent cardiac signals modulate attentional engagement to low spatial frequency fearful faces. Cortex, 104, 232-240. doi:10.1016/j.cortex.2017.06.016
  Abstract View in KAR View full text
  Despite the growing consensus that the continuous dynamic cortical representations of internal bodily states shape the subjective experience of emotions, physiological arousal is typically considered only a consequence and rarely a determinant of the emotional experience. Recent experimental approaches study how afferent autonomic signals from the heart modulate the processing of sensory information by focussing on the phasic properties of arterial baroreceptor firing that is active during cardiac systole and quiescent during cardiac diastole. For example, baroreceptor activation has been shown to enhance the processing of threat-signalling stimuli. Here, we investigate the role of cardiac afferent signals in the rapid engagement and disengagement of attention to fear stimuli. In an adapted version of the emotional attentional cueing paradigm, we timed the presentation of cues, either fearful or neutral faces, to coincide with the different phases of the cardiac cycle. Moreover, we presented cues with different spatial frequency ranges to investigate how these interoceptive signals influence the processing of visual information. Results revealed a selective enhancement of attentional engagement to low spatial frequency fearful faces presented during cardiac systole relative to diastole. No cardiac cycle effects were observed to high spatial frequency nor broad spatial frequency cues. These findings expand our mechanistic understanding of how body–brain interactions may impact the visual processing of fearful stimuli and contribute to the increased attentional capture of threat signals.
• Apps, M., McKay, R., Azevedo, R., Whitehouse, H., & Tsakiris, M. (2018). Not on my team: Medial prefrontal cortex responses to ingroup fusion and unfair monetary divisions. Brain and Behavior, 8, e01030. doi:10.1002/brb3.1030
  Abstract View in KAR View full text
  Objective
  People are highly attuned to fairness, with people willingly suffering personal costs to prevent others benefitting from unfair acts. Are fairness judgments influenced by group alignments? A new theory posits that we favor ingroups and denigrate members of rival outgroups when our personal identity is fused to a group. Although the mPFC has been separately implicated in group membership and fairness processing, it is unclear whether group alignments affect medial prefrontal cortex (mPFC) activity in response to fairness. Here, we examine the contribution of different regions of the mPFC to processing from ingroup and outgroup members and test whether its response differs depending on how fused we are to an ingroup.
  
  Methods
  Subjects performed rounds of the Ultimatum Game, being offered fair or unfair divisions of money from supporters of the same soccer team (ingroup), the fiercest rival (outgroup) or neutral individuals whilst undergoing functional Magnetic Resonance Imaging (fMRI).
  
  Results
  Strikingly, people willingly suffered personal costs to prevent outgroup members benefitting from both unfair and fair offers. Activity across dorsal and ventral (VMPFC) portions of the mPFC reflected an interaction between fairness and group membership. VMPFC activity in particular was consistent with it coding one's fusion to a group, with the fairness by group membership interaction correlating with the extent that the responder's identity was fused to the ingroup.
  
  Conclusions
  The influence of fusion on social behavior therefore seems to be linked to processing in the VMPFC.
• Azevedo, R., Panasiti, M., Maglio, R., & Aglioti, S. (2018). Perceived warmth and competence of others shape voluntary deceptive behaviour in a morally relevant setting. British Journal of Psychology, 109, 25-44. doi:10.1111/bjop.12245
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  The temptation to deceive others compares to a moral dilemma: it involves a conflict between the temptation to obtain some benefit and the desire to conform to personal and social moral norms or avoid aversive social consequences. Thus, people might feel different levels of emotional and moral conflict depending on the target of the deception. Here we explored, in a morally relevant setting, how social judgements based on two fundamental dimensions of human social cognition – ‘warmth’ and ‘competence’ – impact on the decision to deceive others. Results revealed independent effects for warmth and competence. Specifically, while people are less inclined to deceive for self‐gain those individuals they perceive as warm, they also tend to lie more to highly competent others. Furthermore, the perceived warmth and competence modulated the general tendency to reduce deceptive behaviour when there was a risk of disclosure compared to when the lying was anonymous, highlighting the importance of these judgements in social evaluation processes. Together, our results demonstrate that the emotional costs and personal moral standards that inhibit engagement in deceptive behaviour are not stable but rather malleable according to the target and the consequences of the deception.
• Azevedo, R., & Tsakiris, M. (2017). Art reception as an interoceptive embodied predictive experience. Behavioral and Brain Sciences, 40, e350. doi:10.1017/S0140525X17001856
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  In the Distancing-Embracing model, an explanation is proposed for the apparent paradox that is the enjoyment of negative emotional states in art reception. Here, we argue for the advantages of grounding the psychological dynamics described in the model in established and empirically testable frameworks of brain functioning by thinking of art reception as an embodied experience guided by predictive coding.
• Azevedo, R., Bennett, N., Bilicki, A., Hooper, J., Markopoulou, F., & Tsakiris, M. (2017). The calming effect of a new wearable device during the anticipation of public speech. Scientific Reports, 7, 2285. doi:10.1038/s41598-017-02274-2
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  We assessed the calming effect of doppel, a wearable device that delivers heartbeat-like tactile stimulation on the wrist. We tested whether the use of doppel would have a calming effect on physiological arousal and subjective reports of state anxiety during the anticipation of public speech, a validated experimental task that is known to induce anxiety. Two groups of participants were tested in a single-blind design. Both groups wore the device on their wrist during the anticipation of public speech, and were given the cover story that the device was measuring blood pressure. For only one group, the device was turned on and delivered a slow heartbeat-like vibration. Participants in the doppel active condition displayed lower increases in skin conductance responses relative to baseline and reported lower anxiety levels compared to the control group. Therefore, the presence, as opposed to its absence, of a slow rhythm, which in the present study was instantiated as an auxiliary slow heartbeat delivered through doppel, had a significant calming effect on physiological arousal and subjective experience during a socially stressful situation. This finding is discussed in relation to past research on responses and entrainment to rhythms, and their effects on arousal and mood.
• Sel, A., Azevedo, R., & Tsakiris, M. (2017). Heartfelt Self: Cardio-Visual Integration Affects Self-Face Recognition and Interoceptive Cortical Processing. Cerebral Cortex, 27, 5144-5155. doi:10.1093/cercor/bhw296
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  The sense of body-ownership relies on the representation of both interoceptive and exteroceptive signals coming from one's body. However, it remains unknown how the integration of bodily signals coming from “outside” and “inside” the body is instantiated in the brain. Here, we used a modified version of the Enfacement Illusion to investigate whether the integration of visual and cardiac information can alter self-face recognition (Experiment 1) and neural responses to heartbeats (Experiment 2). We projected a pulsing shade, that was synchronous or asynchronous with the participant's heartbeat, onto a picture depicting the participant's face morphed with the face of an unfamiliar other. Results revealed that synchronous (vs. asynchronous) cardio-visual stimulation led to increased self-identification with the other's face (Experiment 1), while during stimulation, synchronicity modulated the amplitude of the Heartbeat Evoked Potential, an electrophysiological index of cortical interoceptive processing (Experiment 2). Importantly, the magnitude of the illusion-related effects was dependent on, and increased linearly, with the participants’ Interoceptive Accuracy. These results provide the first direct neural evidence for the integration of interoceptive and exteroceptive signals in bodily self-awareness.
• Azevedo, R., Garfinkel, S., Critchley, H., & Tsakiris, M. (2017). Cardiac afferent activity modulates the expression of racial stereotypes. Nature Communications, 8, 13854. doi:10.1038/ncomms13854
  Abstract View in KAR View full text
  Negative racial stereotypes tend to associate Black people with threat. This often leads to the misidentification of harmless objects as weapons held by a Black individual. Yet, little is known about how bodily states impact the expression of racial stereotyping. By tapping into the phasic activation of arterial baroreceptors, known to be associated with changes in the neural processing of fearful stimuli, we show activation of race-threat stereotypes synchronized with the cardiovascular cycle. Across two established tasks, stimuli depicting Black or White individuals were presented to coincide with either the cardiac systole or diastole. Results show increased race-driven misidentification of weapons during systole, when baroreceptor afferent firing is maximal, relative to diastole. Importantly, a third study examining the positive Black-athletic stereotypical association fails to demonstrate similar modulations by cardiac cycle. We identify a body–brain interaction wherein interoceptive cues can modulate threat appraisal and racially biased behaviour in context-dependent ways.
• Azevedo, R., Aglioti, S., & Lenggenhager, B. (2016). Participants’ above-chance recognition of own-heart sound combined with poor metacognitive awareness suggests implicit knowledge of own heart cardiodynamics. Scientific Reports, 6, 26545. doi:10.1038/srep26545
  Abstract View in KAR View full text
  Mounting evidence suggests that interoceptive signals are fundamentally important for the experience of the self. Thus far, studies on interoception have mainly focused on the ability to monitor the timing of ongoing heartbeats and on how these influence emotional and self-related processes. However, cardiac afferent signalling is not confined to heartbeat timing and several other cardiac parameters characterize cardiodynamic functioning. Building on the fact that each heart has its own self-specific cardio-dynamics, which cannot be expressed uniquely by heart rate, we devised a novel task to test whether people could recognize the sound of their own heart even when perceived offline and thus not in synchrony with ongoing heartbeats. In a forced-choice paradigm, participants discriminated between sounds of their own heartbeat (previously recorded with a Doppler device) versus another person’s heart. Participants identified the sound of their own heart above chance, whereas their metacognition of performance – as calculated by contrasting performance against ratings of confidence - was considerably poorer. These results suggest an implicit access to fine-grained neural representations of elementary cardio-dynamic parameters beyond heartbeat timing.
• Azevedo, R., Ainley, V., & Tsakiris, M. (2015). Cardio-visual integration modulates the subjective perception of affectively neutral stimuli. International Journal of Psychophysiology, 99, 10-17. doi:10.1016/j.ijpsycho.2015.11.011
  Abstract View in KAR View full text
  Interoception, which refers to the perception of internal body signals, has been consistently associated with emotional processing and with the sense of self. However, its influence on the subjective appraisal of affectively neutral and body-unrelated stimuli is still largely unknown. Across two experiments we sought to investigate this issue by asking participants to detect changes in the flashing rhythm of a simple stimulus (a circle) that could either be pulsing synchronously with their own heartbeats or following the pattern of another person's heart. While overall task performance did not vary as a function of cardio-visual synchrony, participants were better at identifying trials in which no change occurred when the flashes were synchronous with their own heartbeats. This study adds to the growing body of research indicating that we use our body as a reference point when perceiving the world; and extends this view by focusing on the role that signals coming from inside the body, such as heartbeats, may play in this referencing process. Specifically we show that private interoceptive sensations can be combined with affectively neutral information unrelated to the self to influence the processing of a multisensory percept. Results are discussed in terms of both standard multisensory integration processes and predictive coding theories.

Book section

• De Beukelaer, S., Azevedo, R., & Tsakiris, M. (2018). Relating movements in aesthetic spaces: Immersing, distancing, and remembering. In J. F. Christensen & A. Gomila (Eds.), The Arts and The Brain: Psychology and Physiology Beyond Pleasure (Vol. 237, pp. 455-469). Elsevier. doi:10.1016/bs.pbr.2018.03.014
  Abstract View in KAR
  According to Aby Warburg, the aesthetic experience is informed by a pendulum-like movement of the observer's mind that allows him to immerse as well as to take distance from the artwork's composing elements. To account for Warburg's definition, we are proposing embodied simulation and associative processing as constitutive mechanisms of this pendulum-like movement within the aesthetic experience that enable the observer to relate to the displayed artistic material within aesthetic spaces. Furthermore, we suggest that associative processing elicits constructive memory processes that permit the development of a knowledge within which the objects of art become part of memory networks, potentially informing future ways of thinking, feeling, and behaving in real-world situations, as an individual or collectively.