Impact of cardiac interoception cues and confidence on voluntary decisions to make or withhold action in an intentional inhibition task

When the heart inhibits the brain: Cardiac phases modulate short-interval intracortical inhibition

The phasic cardiovascular activity influences the central nervous system through the systolic baroreceptor inputs, inducing widespread inhibitory effects on behavior. Through transcranial magnetic stimulation (TMS) delivered during resting-state over the left primary motor cortex and across the different cardiac phases, we measured corticospinal excitability (CSE) and distinct indices of intracortical motor inhibition: short (SICI) and long (LICI) interval, corresponding to GABAA and GABAB neurotransmission, respectively. We found a significant effect of the cardiac phase on short-intracortical inhibition, without any influence on LICI. Specifically, SICI was stronger at systole compared to diastole. These results show a tight relationship between the cardiac cycle and the inhibitory neurotransmission within M1, and in particular with GABAA-ergic-mediated motor inhibition. We hypothesize that this process requires greater motor control via the gating mechanism and that this, in turn, needs to be recalibrated through the modulation of intracortical inhibition.

Where is an emotion? Using an emotional spatial cueing task to test for emotional localization following targeted visceroception

The relationship between emotion and attention is vital for adaptation. Trained attention to bodily sensations can heighten emotional awareness, including during "visceroception" (sensing the viscera, principally the heart, lungs and gut), which has been linked to emotion intensity and regulation. However, it is not always clear when bodily attention is adaptive, and useful to maintain, or maladaptive and best inhibited. The current study, part of a wider exploratory project, investigates "localized emotion" in this context. Localized emotion is a novel construct, articulated within the project, and suggested to be manifested within a visceroceptive system: targeted visceroception could result in disinhibited attention to localized emotion. In particular, whilst evidence points to the importance of the gastrointestinal tract for emotion (e.g., gut biome, enteric nervous system), gut sensations are often barely detectable, consistent with an inhibition process. An emotional spatial cueing task was used to test for localized effects within several groups: one trained for 8 weeks to focus on their lower abdomen (gastroception), with another focused on their chest cavity (cardioception), plus a control group. The spatial cueing task involved rapid responding to the detection of bodily feelings following the presentation of an emotional picture. Participants then indicated on a body map where they had detected the feeling, followed by corresponding valence and arousal levels (i.e., core affect) on a self-assessment manikin. Data were analyzed using generalized estimating equations. There was some support for localization in the gastroception group relative to the chest-focused group and controls. Gastroception-related findings included: greater improvement in interoception (interoceptive sensibility), slowed reaction times, a cluster of lower abdominal detections on a body map, changes in core affect, and indications of improved emotion regulation. Attending to the gut may play a key role in improving one's ability to access emotional feeling, with associated implications for emotion regulation.

Elevated representational similarity of voluntary action and inhibition in Tourette syndrome

Many people with Tourette syndrome are able to volitionally suppress tics, under certain circumstances. To understand better the neural mechanisms that underlie this ability, we used functional magnetic resonance neuroimaging to track regional brain activity during performance of an intentional inhibition task. On some trials, Tourette syndrome and comparison participants internally chose to make or withhold a motor action (a button press), while on other trials, they followed 'Go' and 'NoGo' instructions to make or withhold the same action. Using representational similarity analysis, a functional magnetic resonance neuroimaging multivariate pattern analysis technique, we assessed how Tourette syndrome and comparison participants differed in neural activity when choosing to make or to withhold an action, relative to externally cued responses on Go and NoGo trials. Analyses were pre-registered, and the data and code are publicly available. We considered similarity of action representations within regions implicated as critical to motor action release or inhibition and to symptom expression in Tourette syndrome, namely the pre-supplementary motor area, inferior frontal gyrus, insula, caudate nucleus and primary motor cortex. Strikingly, in the Tourette syndrome compared to the comparison group, neural activity within the pre-supplementary motor area displayed greater representational similarity across all action types. Within the pre-supplementary motor area, there was lower response-specific differentiation of activity relating to action and inhibition plans and to internally chosen and externally cued actions, implicating the region as a functional nexus in the symptomatology of Tourette syndrome. Correspondingly, patients with Tourette syndrome may experience volitional tic suppression as an effortful and tiring process because, at the top of the putative motor decision hierarchy, activity within the population of neurons facilitating action is overly similar to activity within the population of neurons promoting inhibition. However, not all pre-supplementary motor area group differences survived correction for multiple comparisons. Group differences in representational similarity were also present in the primary motor cortex. Here, representations of internally chosen and externally cued inhibition were more differentiated in the Tourette syndrome group than in the comparison group, potentially a consequence of a weaker voluntary capacity earlier in the motor hierarchy to suppress actions proactively. Tic severity and premonitory sensations correlated with primary motor cortex and caudate nucleus representational similarity, but these effects did not survive correction for multiple comparisons. In summary, more rigid pre-supplementary motor area neural coding across action categories may constitute a central feature of Tourette syndrome, which can account for patients' experience of 'unvoluntary' tics and effortful tic suppression.

Self-reported interoceptive accuracy and interoceptive attention differentially correspond to measures of visual attention and self-regard

Background

Interoception, the perception of bodily functions and sensations, is a crucial contributor to cognition, emotion, and well-being. However, the relationship between these three processes is not well understood. Further, it is increasingly clear that dimensions of interoception differentially corresponds to these processes, yet this is only recently being explored. The present study addresses two important questions: Are subjective interoceptive accuracy and interoceptive attention related to self-regard and well-being? And are they related to exteroceptive (visual) attention?

Methods

Participants (N = 98; 29% women; aged 23-64 years) completed: a battery of questionnaires to assess subjective accuracy (how well one predicts bodily sensations), interoceptive attention (a tendency to notice bodily signals), self-regard (self-esteem, self-image, life satisfaction), state negative affect (depression, anxiety, and stress), a self-esteem Implicit Association Task (a measure of implicit self-esteem), and a flanker task to assess visual selective attention. Subjective interoceptive accuracy and attention served as dependent variables. Correlations and principal component analysis was used to establish correlations among variables and determine how, or whether, these measures are associated with subjective interoceptive accuracy or attention.

Results

Greater scores on measures of self-regard, implicit self-esteem, cognition and lower negative affect were broadly associated with greater subjective interoceptive accuracy. Conversely, only explicit self-esteem, satisfaction with life, and self-image corresponded to subjective interoceptive attention. An exploratory analysis with a more inclusive scale of interoceptive attention was conducted. Results of this exploratory analysis showed that the broader measure was a stronger correlate to self-regard than subjective interoceptive accuracy, though it, too, did not correlate with visual attention. In short, both subjective interoceptive accuracy and attention corresponded to well-being and mental health, but only accuracy was associated with exteroceptive attention.

Conclusion

These results add to a growing literature suggesting different dimensions of (subjective) interoception differentially correspond to indices of well-being. The links between exteroceptive and interoceptive attention, and their association with merit further study.

Interoceptive accuracy is associated with benefits in decision making in children

Introduction

Decision making results not only from logical analyses, but seems to be further guided by the ability to perceive somatic information (interoceptive accuracy). Relations between interoceptive accuracy and decision making have been exclusively studied in adults and with regard to complex, uncertain situations (as measured by the Iowa Gambling Task, IGT).

Methods

In the present study, 1454 children (6-11 years) were examined at two time points (approximately 1 year apart) using an IGT as well as a delay-of-gratification task for sweets-items and toy-items. Interoceptive accuracy was measured using a child-adapted version of the Heartbeat Perception Task.

Results

The present results revealed that children with higher, as compared to lower, interoceptive accuracy showed more advantageous choices in the IGT and delayed more sweets-items, but not toy-items, in a delay-of-gratification task at time point 2 but not at time point 1. However, no longitudinal relation between interoceptive accuracy and decision making 1 year later could be shown.

Discussion

Results indicate that interoceptive accuracy relates to decision-making abilities in situations of varying complexity already in middle childhood, and that this link might consolidate across the examined 1-year period. Furthermore, the association of interoceptive accuracy and the delay of sweets-items might have implications for the regulation of body weight at a later age.

Reliability of the Heartbeat Tracking Task to Assess Interoception

Interoception refers to the competence in perceiving and interpreting internal sensations emerging from the body. The most common approach to assess interoception is through cardiac interoceptive tests like the heartbeat tracking task (HTT), which measures the accuracy on perceive and counting heartbeats during a period. However, the literature is scarce in providing adequate reliability evidence for this measure so that the interoception assessment may be threaten. In addition to HTT accuracy, it is possible to determine sensibility (self-reported confidence) and interoceptive awareness (correspondence between accuracy and sensibility). Thus, we measured the test-retest reliability of HTT and also investigated the behavior of HTT outcomes along the task. Therefore, 31 healthy adults (16 males) with 27.8 (9.4) years old performed two consecutive HTT interspersed by one day. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable difference (MD) analyzes showed 'Good' relative reliability for interoceptive accuracy (ICC = 0.880; SEM = 0.263; MD = 0.728; p < 0.001) and 'Moderate' for sensibility (ICC = 0.617; SEM = 0.648; MD = 1.797; p < 0.001) and awareness (ICC = 0.593; SEM = 0.227; MD = 0.628; p < 0.001). The absolute reliability shows low threshold values for observing true effects in HTT outcomes. The results also showed that reducing the number of HTT blocks did not impact the outcomes. The HTT showed to be reliable in determine the interoceptive competences in healthy adults.

RapidHRV: an open-source toolbox for extracting heart rate and heart rate variability

Heart rate and heart rate variability have enabled insight into a myriad of psychophysiological phenomena. There is now an influx of research attempting using these metrics within both laboratory settings (typically derived through electrocardiography or pulse oximetry) and ecologically-rich contexts (via wearable photoplethysmography, i.e., smartwatches). However, these signals can be prone to artifacts and a low signal to noise ratio, which traditionally are detected and removed through visual inspection. Here, we developed an open-source Python package, RapidHRV, dedicated to the preprocessing, analysis, and visualization of heart rate and heart rate variability. Each of these modules can be executed with one line of code and includes automated cleaning. In simulated data, RapidHRV demonstrated excellent recovery of heart rate across most levels of noise (>=10 dB) and moderate-to-excellent recovery of heart rate variability even at relatively low signal to noise ratios (>=20 dB) and sampling rates (>=20 Hz). Validation in real datasets shows good-to-excellent recovery of heart rate and heart rate variability in electrocardiography and finger photoplethysmography recordings. Validation in wrist photoplethysmography demonstrated RapidHRV estimations were sensitive to heart rate and its variability under low motion conditions, but estimates were less stable under higher movement settings.

Environment and body-brain interplay affect inhibition and decision-making

The fine-tuned interplay of brain and body underlies human ability to cope with changes in the internal and external milieus. Previous research showed that cardiac interoceptive changes (e.g., cardiac phase) affect cognitive functions, notably inhibition that is a key element for adaptive behaviour. Here we investigated the influence on cognition of vestibular signal, which provides the brain with sensory information about body position and movement. We used a centrifuge-based design to disrupt vestibular signal in healthy human volunteers while their inhibition and decision-making functions were assessed with the stop-signal paradigm. Participants performed the standard and a novel, sensorial version of the stop-signal task to determine whether disrupted vestibular signal influences cognition as a function of its relevance to the context. First, we showed that disrupted vestibular signal was associated with a larger variability of longest inhibition latencies, meaning that participants were even slower to inhibit in the trials where they had the most difficulty inhibiting. Second, we revealed that processing of bodily information, as required in the sensorial stop-signal task, also led to a larger variability of longest inhibition latencies, which was all the more important when vestibular signal was disrupted. Lastly, we found that such a degraded response inhibition performance was due in part to the acceleration of decision-making process, meaning that participants made a decision more quickly even when strength of sensory evidence was reduced. Taken together, these novel findings provide direct evidence that vestibular signal affects the cognitive functions of inhibition and decision-making.

The Blink and the Body

Abstract. We evaluated the interaction of emotion, interoceptive awareness (IA), and attention using an attentional blink (AB) task. Healthy undergraduates completed a cardiac awareness task and, based on previously validated cut scores, were classified as high or average perceivers (n = 19 in each group; matched on age and gender). Participants completed an AB task with counterbalanced emotional and/or neutral lexical stimuli as the first target (T1) and/or the second target (T2). Both high and average perceivers exhibited retroactive interference in conditions where T2 immediately followed T1. However, only the average perceivers exhibited a significant blink effect: They reported T2 inaccurately in trials in which one intervening stimulus occurred between T1 and T2. High perceivers exhibited their best performance in trials where both targets were emotional; average perceivers exhibited their worst performance in these trials. These results contribute to a small but growing literature that suggests IA and exteroceptive attention are related systems.

Sex differences in interoceptive accuracy: A meta-analysis

Interoceptive accuracy, the ability to correctly perceive internal signals arising from the body, is thought to be disrupted in numerous mental and physical health conditions. Whilst evidence suggests poorer interoceptive accuracy in females compared to males, raising the possibility that interoceptive differences may relate to sex differences in mental and physical health, results concerning sex differences in interoceptive accuracy are mixed. Given such ambiguity, this meta-analysis aimed to establish the presence or absence of sex differences in interoceptive accuracy across cardiac, respiratory, and gastric domains. A review of 7956 abstracts resulted in 93 eligible studies. Results demonstrated superior accuracy in males across cardiac, but not gastric, tasks, while findings on respiratory tasks were mixed. Effect sizes were consistent across cardiac tasks, but instability and/or moderate heterogeneity was observed across other domains, likely due to the small number of eligible studies. Despite such limitations, results indicate the possibility of sex differences across interoception tasks and domains. Methodological limitations concerning the influence of physiological factors, and directions for future research are discussed.

Amplified engagement of prefrontal cortex during control of voluntary action in Tourette syndrome

Tourette syndrome is characterized by ‘unvoluntary’ tics, which are compulsive, yet often temporarily suppressible. The inferior frontal gyrus is implicated in motor control, including inhibition of pre-potent actions through influences on downstream subcortical and motor regions. Although tic suppression in Tourette syndrome also engages the inferior frontal gyrus, it is unclear whether such prefrontal control of action is also dysfunctional: Tic suppression studies do not permit comparison with control groups, and neuroimaging studies of motor inhibition can be confounded by the concurrent expression or suppression of tics. Here, patients with Tourette syndrome were directly compared to control participants when performing an intentional inhibition task during functional MRI. Tic expression was recorded throughout for removal from statistical models. Participants were instructed to make a button press in response to Go cues, withhold responses to NoGo cues, and decide whether to press or withhold to ‘Choose’ cues. Overall performance was similar between groups, for both intentional inhibition rates (% Choose-Go) and reactive NoGo inhibition commission errors. A subliminal face prime elicited no additional effects on intentional or reactive inhibition. Across participants, the task activated prefrontal and motor cortices and subcortical nuclei, including pre-supplementary motor area, inferior frontal gyrus, insula, caudate nucleus, thalamus and primary motor cortex. In Tourette syndrome, activity was elevated in the inferior frontal gyrus, insula and basal ganglia, most notably within the right inferior frontal gyrus during voluntary action and inhibition (Choose-Go and Choose-NoGo), and reactive inhibition (NoGo-correct). Anatomically, the locus of this inferior frontal gyrus hyperactivation during control of voluntary action matched that previously reported for tic suppression. In Tourette syndrome, activity within the caudate nucleus was also enhanced during both intentional (Choose-NoGo) and reactive (NoGo-correct) inhibition. Strikingly, despite the absence of overt motor behaviour, primary motor cortex activity increased in patients with Tourette syndrome but decreased in controls during both reactive and intentional inhibition. Additionally, severity of premonitory sensations scaled with functional connectivity of the pre-supplementary motor area to the caudate nucleus, globus pallidus and thalamus when choosing to respond (Choose-Go). Together, these results suggest that patients with Tourette syndrome use equivalent prefrontal mechanisms to suppress tics and withhold non-tic actions, but require greater inferior frontal gyrus engagement than controls to overcome motor drive from hyperactive downstream regions, notably primary motor cortex. Moreover, premonitory sensations may cue midline motor regions to generate tics through interactions with the basal ganglia.

Linking perception of bodily states and cognitive control: the role of interoception in impulsive behaviour

Interoception and impulsivity are two multi-dimensional constructs and although the role of interoception in impulsiveness has been previously reported, it is not clear whether their different facets are related to each other. In the present study, we aimed at bridging this gap by investigating the relationships between interoception and impulsivity in the light of their multi-dimensional nature. To this aim, we conducted a cross-task comparison and assessed in the same sample of healthy participants, interoceptive accuracy, by the heartbeat perception task, interoceptive sensibility, by a self-reported measure, "hot" impulsivity, by a behavioural task of risk taking, and "cool" impulsivity, by a go/no-go task. Also, we assessed trait impulsivity by a self-report measure. We found that interoceptive sensibility contributed to "hot" impulsivity, while interoceptive accuracy was related to non-planning trait impulsivity. These findings underscore the need to investigate at a finer grain the relationships between these two complex, multi-dimensional constructs.

Co-emergence Reinforcement and Its Relevance to Interoceptive Desensitization in Mindfulness and Therapies Aiming at Transdiagnostic Efficacy

Interoception, the ability to feel the body's internal sensations, is an essential aspect of emotional experience. There is mounting evidence that interoception is impaired in common mental health disorders and that poor interoceptive awareness is a major contributor to emotional reactivity, calling for clinical interventions to address this deficit. The manuscript presents a comprehensive theoretical review, drawing on multidisciplinary findings to propose a metatheory of reinforcement mechanisms applicable across a wide range of disorders. We present a reconsideration of operant conditioning through the co-emergence model of reinforcement, which is a neurophenomenological account of the interaction between cognition and interoception, and its consequences on behavior. The model suggests that during memory processing, the retrieval of autobiographical memory (including maladaptive cognition) is dependent upon its co-emerging interoceptive cues occurring at the encoding, consolidation and reconsolidation stages. Accordingly, "interoceptive reinforcement" during emotional distress is a common factor to all emotional disorders and a major cause for relapse. We propose that interoceptive desensitization has transdiagnostic benefits, readily achievable through the cultivation of equanimity during mindfulness training and can be integrated in cognitive and behavioral interventions to permit a transdiagnostic applicability. We summarize the contributions of this approach into 10 specific and testable propositions.

Feeling in Control: The Role of Cardiac Timing in the Sense of Agency

The sense of agency describes the experience of controlling one’s body to cause desired effects in the world. We explored whether this is influenced by interoceptive processes. Specifically, we investigated whether the sense of agency changes depending on where, in the cardiac cycle (systole or diastole), the action was executed and where the outcome of the action occurred. In two experiments, participants completed decision-making task to win/lose money. Explicit (ratings of control) and implicit (temporal judgement) measures of agency were differentially affected by cardiovascular state. Implicit agency scores were affected by the cardiac phase at the point of action execution. Explicit ratings of control were affected by the type of (free vs. instructed) and by outcome valence (win vs. lose). The time of the action was uniformly distributed across the cardiac cycle. These results show interoceptive impact on agency, but that cardiac cycle may affect explicit and implicit agency differently.

Effects of interoceptive training on decision making, anxiety, and somatic symptoms

Background

Interoception is the perception of afferent information that arises from any point within the body. Individual differences in interoception have been associated with affective processing and decision-making processing. The somatic marker hypothesis summarizes the potential effects of interoception on decision-making processes. According to this theory, individuals with interoceptive dysfunction exhibit disadvantageous decision making. Recently, enhancement of interoceptive accuracy, an element of interoception assessed by objective decision-making tasks, has been demonstrated using biofeedback. Garfinkle et al. developed an interoceptive training task, modified from the heartbeat perception task, which enhanced interoceptive accuracy and reduced anxiety symptoms. The purpose of this study was to determine the effects of interoceptive training on decision-making processes. Based on improvements in interoceptive accuracy, we hypothesized that decision-making scores would change in a manner indicative of increased rationality.

Methods

This longitudinal interventional study was performed with interoceptive training. Before and after the intervention, interoceptive accuracy and rationality of decision-making processes were assessed using a heartbeat perception task and rational decision-making tasks, respectively. Fourteen healthy volunteers (nine women; mean age, 21.9 ± 4.5 years) participated. The analysis included data from 12 participants. To detect individual differences in the effects of interoceptive accuracy on rationality of decision making, correlation analysis was conducted on change ratios of the indices of interoceptive accuracy and rationality of decision making.

Results

Interoceptive training resulted in significant enhancement of interoceptive accuracy scores and significant reductions in somatic symptom and state anxiety scores. In contrast, interoceptive training did not cause significant changes in decision-making indices. There was a significant positive correlation between change ratios of indices of interoceptive accuracy and rationality of decision making.

Conclusions

The results suggested a causal relation between interoception and rationality of decision making. These findings will enhance the understanding of mechanisms underlying alterations of decision-making related to psychotherapy by focusing on interoception.

Trial registration

Trial registration number: UMIN000037548.