Interoceptive Integration Research Articles

Preliminary evidence for altered brain-heart coherence during anxiogenic movies

Abstract During states of anxiety, fundamental threat circuitry in the brain can increase heart rate via alterations in autonomic balance (increased sympathetic activity and parasympathetic withdrawal) and may serve to promote interoceptive integration and awareness of cardiac signals. Moreover, evidence indicates pathological anxiety could be associated with increased communication between the brain and the heart. Yet, this phenomenon remains not well understood. For instance, studies in this area have been conducted within the confines of tightly controlled experimental paradigms. Whether anxiety impacts brain-heart communication outside of such experimental settings, and in relatively more naturalistic contexts, is less clear. Here, we used a suspenseful movie fMRI paradigm to study induced anxiety (n = 29 healthy volunteers; Caltech Conte dataset; Kliemann et al., 2022). We predicted that brain responses across an anxiety-relevant “defensive response network” (amygdala, hypothalamus, periaqueductal gray, bed nucleus of the stria terminalis, dorsomedial prefrontal cortex, ventromedial prefrontal cortex, subgenual anterior cingulate, and anterior insula; Abend et al., 2022) would show increased coherence with heart rate as participants watched a suspenseful movie clip compared to a non-suspenseful movie clip. Counter to our predictions, we found decreased coherence between heart rate and brain responses during increased anxiety, namely in amygdala-prefrontal circuitry. We suggest these alterations may be underpinned by parasympathetic withdrawal and/or decreased interoceptive awareness during suspenseful movie-watching.

Arousal coherence, uncertainty, and well-being: an active inference account.

Here we build on recent findings which show that greater alignment between our subjective experiences (how we feel) and physiological states (measurable changes in our body) plays a pivotal role in the overall psychological well-being. Specifically, we propose that the alignment or 'coherence' between affective arousal (e.g. how excited we 'feel') and autonomic arousal (e.g. heart rate or pupil dilation) may be key for maintaining up-to-date uncertainty representations in dynamic environments. Drawing on recent advances in interoceptive and affective inference, we also propose that arousal coherence reflects interoceptive integration, facilitates adaptive belief updating, and impacts our capacity to adapt to changes in uncertainty, with downstream consequences to well-being. We also highlight the role of meta-awareness of arousal, a third level of inference, which may permit conscious awareness, learning about, and intentional regulation of lower-order sources of arousal. Practices emphasizing meta-awareness of arousal (like meditation) may therefore elicit some of their known benefits via improved arousal coherence. We suggest that arousal coherence is also likely to be associated with markers of adaptive functioning (like emotional awareness and self-regulatory capacities) and discuss mind-body practices that may increase coherence.

Dissociative Symptoms and Interoceptive Integration.

Dissociative symptoms and disorders of dissociation are characterised by disturbances in the experience of the self and the surrounding world, manifesting as a breakdown in the normal integration of consciousness, memory, identity, emotion, and perception. This paper aims to provide insights into dissociative symptoms from the perspective of interoception, the sense of the body's internal physiological state, adopting a transdiagnostic framework.Dissociative symptoms are associated with a blunting of autonomic reactivity and a reduction in interoceptive precision. In addition to the central function of interoception in homeostasis, afferent visceral signals and their neural and mental representation have been shown to shape emotional feeling states, support memory encoding, and contribute to self-representation. Changes in interoceptive processing and disrupted integration of interoceptive signals into wider cognition may contribute to detachment from the body and the world, blunted emotional experience, and altered subjective recall, as experienced by individuals who suffer from dissociation.A better understanding of the role of altered interoceptive integration across the symptom areas of dissociation could thus provide insights into the neurophysiological mechanisms underlying dissociative disorders. As new therapeutic approaches targeting interoceptive processing emerge, recognising the significance of interoceptive mechanisms in dissociation holds potential implications for future treatment targets.

From the inside out: Interoceptive feedback facilitates the integration of visceral signals for efficient sensory processing

Neuroscientific studies have mainly focused on the way humans perceive and interact with the external world. Recent work in the interoceptive domain indicates that the brain predictively models information from inside the body such as the heartbeat and that the efficiency with which this is executed can have implications for exteroceptive processing. However, to date direct evidence underpinning these hypotheses is lacking. Here, we show how the brain predictively refines neural resources to process afferent cardiac feedback and uses these interoceptive cues to enable more efficient processing of external sensory information. Participants completed a repetition-suppression paradigm consisting of a neutral repeating face. During the first face presentation, they heard auditory feedback of their heartbeat which either coincided with the systole of the cardiac cycle, the time at which cardiac events are registered by the brain or the diastole during which the brain receives no internal cardiac feedback. We used electroencephalography to measure the heartbeat evoked potential (HEP) as well as auditory (AEP) and visual evoked potentials (VEP). Exteroceptive cardiac feedback which coincided with the systole produced significantly higher HEP amplitudes relative to feedback timed to the diastole. Elevation of the HEP in this condition was followed by significant suppression of the VEP in response to the repeated neutral face and a stepwise decrease of AEP amplitude to repeated heartbeat feedback. Our results hereby show that exteroceptive heartbeat feedback coinciding with interoceptive signals at systole enhanced interoceptive cardiac processing. Furthermore, the same cue facilitating interoceptive integration enabled efficient suppression of a visual stimulus, as well as repetition suppression of the AEP across successive auditory heartbeat feedback. Our findings provide evidence that the alignment of external to internal signals can enhance the efficiency of interoceptive processing and that cues facilitating this process in either domain have beneficial effects for internal as well as external sensory processing.

Association of chronic inflammation and perceived stress with abnormal functional connectivity in brain areas involved with interoception in hepatitis C patients

BackgroundSickness behavioral changes elicited by inflammation may become prolonged and dysfunctional in patients with chronic disease, such as chronic hepatitis C (CHC). Neuroimaging studies show that the basal ganglia and insula are sensitive to systemic inflammation. AimTo elucidate the clinical and neurobiological aspects of prolonged illnesses in patients with CHC. MethodsThirty-five CHC patients not treated with interferon-α or other antiviral therapy, and 30 control subjects matched for age and sex, were evaluated for perceived stress (perceived stress scale; PSS), depression (PHQ-9), fatigue and irritability through a visual analog scale (VAS), as well as serum levels of interleukin-6 (IL-6), prostaglandin E2 (PGE2) and oxidative stress markers. Functional MRI was performed, measuring resting-state functional connectivity using a region-of-interest (seed)-based approach focusing on the bilateral insula, subgenual anterior cingulate cortex and bilateral putamen. Between-group differences in functional connectivity patterns were assessed with two-sample t-tests, while the associations between symptoms, inflammatory markers and functional connectivity patterns were analyzed with multiple regression analyses. ResultsCHC patients had higher PSS, PHQ-9 and VAS scores for fatigue and irritability, as well as increased IL-6 levels, PGE2 concentrations and antioxidant system activation compared to controls. PSS scores positively correlated with functional connectivity between the right anterior insula and right putamen, whereas PHQ-9 scores correlated with functional connectivity between most of the seeds and the right anterior insula. PGE2 (positively) and IL-6 (negatively) correlated with functional connectivity between the right anterior insula and right caudate nucleus and between the right ventral putamen and right putamen/globus pallidus. PGE2 and PSS scores accounted for 46% of the variance in functional connectivity between the anterior insula and putamen. ConclusionsCHC patients exhibited increased perceived stress and depressive symptoms, which were associated with changes in inflammatory marker levels and in functional connectivity between the insula and putamen, areas involved in interoceptive integration, emotional awareness, and orientation of motivational state.

Effects of a Mindfulness Meditation App on Subjective Well-Being: Active Randomized Controlled Trial and Experience Sampling Study.

BackgroundMindfulness training (MT) includes a variety of contemplative practices aimed at promoting intentional awareness of experience, coupled with attitudes of nonjudgment and curiosity. Following the success of 8-week, manualized group interventions, MT has been implemented in a variety of modalities, including smartphone apps that seek to replicate the success of group interventions. However, although smartphone apps are scalable and accessible to a wider swath of population, their benefits remain largely untested.ObjectiveThis study aimed to investigate a newly developed MT app called Wildflowers, which was codeveloped with the laboratory for use in mindfulness research. It was hypothesized that 3 weeks of MT through this app would improve subjective well-being, attentional control, and interoceptive integration, albeit with weaker effects than those published in the 8 week, manualized group intervention literature.MethodsUndergraduate students completed 3 weeks of MT with Wildflowers (n=45) or 3 weeks of cognitive training with a game called 2048 (n=41). State training effects were assessed through pre- and postsession ratings of current mood, stress level, and heart rate. Trait training effects were assessed through pre- and postintervention questionnaires canvassing subjective well-being and behavioral task measures of attentional control and interoceptive integration. State and trait training data were analyzed in a multilevel model using emergent latent factors (acceptance, awareness, and openness) to summarize the trait questionnaire battery.ResultsAnalyses revealed both state and trait effects specific to MT; participants engaging in MT demonstrated improved mood (r=.14) and a reduction of stress (r=−.13) immediately after each training session compared with before the training session and decreased postsession stress over 3 weeks (r=−.08). In addition, MT relative to cognitive training resulted in greater improvements in attentional control (r=−.24). Interestingly, both groups demonstrated increased subjective ratings of awareness (r=.28) and acceptance (r=.23) from pre- to postintervention, with greater changes in acceptance for the MT group trending (r=.21).ConclusionsMT, using a smartphone app, may provide immediate effects on mood and stress while also providing long-term benefits for attentional control. Although further investigation is warranted, there is evidence that with continued usage, MT via a smartphone app may provide long-term benefits in changing how one relates to their inner and outer experiences.Trial RegistrationClinicalTrials.gov NCT03783793; https://clinicaltrials.gov/ct2/show/NCT03783793 (Archived by WebCite at http://www.webcitation.org/75EF2ehst)

The integration of the internal and external milieu in the insula during dynamic emotional experiences

Whilst external events trigger emotional responses, interoception (the perception of internal physiological states) is fundamental to core emotional experience. By combining high resolution functional neuroimaging with concurrent physiological recordings, we investigated the neural mechanisms of interoceptive integration during free listening to an emotionally salient audio film. We found that cardiac activity, a key interoceptive signal, was robustly synchronised across participants and centrally represented in the posterior insula. Effective connectivity analysis revealed that the anterior insula, specifically tuned to the emotionally salient moments of the audio stream, serves as an integration hub of interoceptive processing: interoceptive states represented in the posterior insula are integrated with exteroceptive representations by the anterior insula to highlight these emotionally salient moments. Our study for the first time demonstrates the insular hierarchy for interoceptive processing during natural emotional experience. These findings provide an ecologically-valid framework for elucidating the neural underpinnings of emotional deficits in neuropsychiatric disorders.

An fMRI Study Examining Effects of Acute D-Cycloserine During Symptom Provocation in Spider Phobia

Exposure-based therapy for anxiety disorders is believed to operate on the basis of fear extinction. Studies have shown acute administration of D-cycloserine (DCS) enhances fear extinction in animals and facilitates exposure therapy in humans, but the neural mechanisms are not completely understood. To date, no study has examined neural effects of acute DCS in anxiety-disordered populations. Two hours prior to functional magnetic resonance imaging scanning, 23 spider-phobic and 23 non-phobic participants were randomized to receive DCS 100 mg or placebo. During scanning, participants viewed spider, butterfly, and Gaussian-blurred baseline images in a block-design paradigm. Diagnostic and treatment groups were compared regarding differential activations to spider versus butterfly stimuli. In the phobic group, DCS enhanced prefrontal (PFC), dorsal anterior cingulate (ACC), and insula activations. For controls, DCS enhanced ventral ACC and caudate activations. There was a positive correlation between lateral PFC and amygdala activation for the placebo-phobic group. Reported distress during symptom provocation was correlated with amygdala activation in the placebo-phobic group and orbitofrontal cortex activation in the DCS-phobic group. Results suggest that during initial phobic symptom provocation DCS enhances activation in regions involved in cognitive control and interoceptive integration, including the PFC, ACC, and insular cortices for phobic participants.