On the Relationship of Interoceptive Accuracy and Attention: A Controlled Study With Depressed Inpatients and a Healthy Cohort

Heart rate variability, interoceptive accuracy and functional connectivity in middle-aged and older patients with depression

BACKGROUND AND OBJECTIVE

Major depressive disorder (MDD) is associated with increased cardiac morbidity. Reduced heart rate variability (HRV) as well as lower interoceptive accuracy (IAc) have been observed in MDD as possible sympathomimetic mechanisms related to insula activity. The salience network (SN) anchored by the insula has been posited as a crucial functional network for cardiac sensations and the default mode network (DMN) for MDD. This study aimed to investigate the relation between insula-centered and depression-related brain networks, IAc and HRV in patients with depression as a possible mechanism by which MDD increases cardiac morbidity.

METHODS

30 depressed inpatients and 30 healthy subjects (derived from the population-based "Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression" cohort study, STAAB) all over 50 years were examined. HRV and IAc were assessed via electrocardiogram and a heartbeat perception task prior to a 3 T resting-state functional magnetic resonance imaging. Seed-to-voxel resting-state functional connectivity (FC) analysis was conducted with six seeds in the insula and two seeds in the DMN.

RESULTS

Depressed patients on the one hand showed decreased FC between insula cortex and frontal as well occipital cortical brain regions compared to controls. Depressed patients on the other hand exhibited higher FC between the medial prefrontal cortex and the insula cortex compared to controls. However, depressed patients did not differ in HRV nor in IAc compared to controls.

CONCLUSION

Thus, differences in insula-related brain networks in depression in our study were not mirrored by differences in HRV and IAc. Future research is needed to define the mechanism by which depression increases cardiac morbidity.

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.

The Effects of a 3-Week Heartbeat Perception Training on Interoceptive Abilities

Recent studies showed promising short-term effects of heartbeat perception training on interoceptive abilities. Research on the effects of heartbeat perception training on interoceptive abilities over time is sparse. Therefore, the aim of this study was to examine the short-term effects and the effects of a 3-week heartbeat perception training over time on interoceptive abilities, namely, cardiac interoceptive accuracy (IAc) and interoceptive sensibility (IS). A total of 40 healthy participants were randomized to the intervention group (n = 20) or the control group (n = 20). The intervention group conducted three cardiac biofeedback sessions (one per week) at the laboratory, whereas the control group watched a documentary instead. Interoceptive abilities were assessed via the heartbeat perception task (IAc) and confidence ratings (IS) at baseline, after each laboratory session, and 1 week after the last session (post-measurement). IAc was significantly increased in the intervention group compared to the control group after the first training session (short-term effect). There were no significant improvements in IS due to the first session, and neither on IAc nor IS over time. Descriptive trends of improved interoceptive abilities over time were found in both groups. Single session of heartbeat perception training seems to be a promising approach to improve IAc. Future research should further investigate the long-term effects of diverse heartbeat perception training varying in frequency and intensity of the training sessions in diverse samples aiming to improve interoceptive abilities.