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Recent studies have associated interoceptive awareness, the perception of internal bodily sensations, with a predictive mechanism of perception across all sensory modalities. According to the framework, volitional attention plays a pivotal role in interoceptive awareness by prioritizing interoceptive sensations over exteroceptive ones. Consequently, it is hypothesized that the presence of irrelevant stimuli would disrupt the attentional modulation and interoceptive awareness, which remains untested. In this study, we investigated if interoceptive awareness is diminished by unrelated auditory distractors to validate the proposed perceptual framework. A total of 30 healthy human volunteers performed the heartbeat counting task both with and without auditory distractors. Additionally, we measured participant's psychophysiological traits related to interoception, including the high-frequency component of heart rate variability (HF-HRV) and trait interoceptive sensibility. The results showed that interoceptive accuracy, confidence, and heartbeat intensity decreased in the presence of distractor sound. Moreover, individuals with higher HF-HRV and a greater tendency to worry about bodily states experienced a more pronounced distractor effect on interoceptive awareness. These results provide support for the perceptual mechanism of interoceptive awareness in terms of the predictive process, highlighting the impact of relative precision across interoceptive and exteroceptive signals on perceptual experiences., Competing Interests: Conflict of interest The authors declare no potential conflict of interest., (Copyright © 2023 Elsevier Ltd and Japan Neuroscience Society. All rights reserved.)

Interoception consists in the perception and processing of internal body signals, such as heartbeat. Previous neuroimaging studies revealed that attention to heartbeat activated bilateral insula and premotor regions. In the present double-blind study, we aimed at testing the role of insula in interoception by means of transcranial direct current stimulation (tDCS) interfering with its activity. Sixteen healthy participants responded to a questionnaire to evaluate the tendency to be internally focused and performed a heartbeat counting task before and after tDCS in three sessions (left insula stimulation, right insula stimulation, sham stimulation). Real and reported heartbeat were recorded and used to calculate the accuracy scores. A significant interaction between stimulation condition and time (pre- and post-stimulation) was found due to a significant improvement of the interoceptive accuracy in the sham condition only. Our results demonstrated that stimulation over the insula reduced the possibility to improve the precision with which individuals detect internal signals., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Recent studies have associated interoceptive awareness, the perception of internal bodily sensations, with a predictive mechanism of perception across all sensory modalities. According to the framework, volitional attention plays a pivotal role in interoceptive awareness by prioritizing interoceptive sensations over exteroceptive ones. Consequently, it is hypothesized that the presence of irrelevant stimuli would disrupt the attentional modulation and interoceptive awareness, which remains untested. In this study, we investigated if interoceptive awareness is diminished by unrelated auditory distractors to validate the proposed perceptual framework. A total of 30 healthy human volunteers performed the heartbeat counting task both with and without auditory distractors. Additionally, we measured participant’s psychophysiological traits related to interoception, including the high-frequency component of heart rate variability (HF-HRV) and trait interoceptive sensibility. The results showed that interoceptive accuracy, confidence, and heartbeat intensity decreased in the presence of distractor sound. Moreover, individuals with higher HF-HRV and a greater tendency to worry about bodily states experienced a more pronounced distractor effect on interoceptive awareness. These results provide support for the perceptual mechanism of interoceptive awareness in terms of the predictive process, highlighting the impact of relative precision across interoceptive and exteroceptive signals on perceptual experiences.

Interoception is involved in both somatic and mental disorders with different prevalence between genders; however, gender differences are often neglected. To examine the potential gender differences in interoceptive awareness, we recruited 376 healthy subjects (51% males, aged 17–30 years), to fill in the Multidimensional Assessment of Interoceptive Awareness (MAIA). Of that sample, in a subgroup of 40 subjects (50% males), interoceptive accuracy was assessed by heartbeat counting task (HCT). The results on interroceptive awareness suggest that females tend to notice bodily sensations more often, better understand relations between bodily sensations and emotional states, worry or experience more emotional distress with sensations of pain or discomfort and see body as less safe. The results of interoceptive accuracy further suggest that females are less efficient in consciously detecting heartbeats. Therefore, gender should be considered when interoceptive evaluation is performed in disorders associated to bodily sensations and to the emotional/mood states. [ABSTRACT FROM AUTHOR]