Raimo, S. | bioRxiv Science

bioRxiv2025

Processing of inner bodily signals: evidence and insight from adolescence

Interoception, the sense of inner bodily signals, plays a key role in emotional regulation, cognition and mental health. While its relevance in adulthood has been extensively explored, less is known about how these abilities develop during adolescence, a period characterised by significant physical and psychological changes. This study aimed to investigate three distinct dimensions of interoception -- accuracy, sensitivity and awareness -- in adolescents and adults to better understand the developmental profile of this sense. Fifty-four adolescents (aged 12-14) and 50 adults (aged 25-34) completed the Heartbeat Monitoring Task to assess their actual ability to detect heartbeats, their confidence in this ability, and the confidence-accuracy correspondence, and a questionnaire on the tendency to focus on bodily sensations. The study also examined where participants localised bodily sensations during the interoceptive task. The results revealed no significant differences in interoceptive accuracy between the two groups. Both age groups exhibited similar body localisation patterns, primarily focusing on the chest during heartbeat detection. However, adolescents showed significantly lower metacognitive awareness of their ability to perceive internal bodily sensations, and higher focus on interoceptive sensations, as reflected in their higher confidence ratings and questionnaire scores. No significant correlations emerged among the three interoceptive dimensions in either group, which supports the view that these dimensions represent independent components of interoception. These findings suggest that, while basic interoceptive detection may be established by early adolescence, the capacity to accurately reflect on these internal sensations continues to mature into adulthood. The mismatch observed between adolescents heightened bodily focus and their limited metacognitive insight may partly help explain why adolescence is a period of increased vulnerability to mental health difficulties.

neuroscience↗

bioRxiv2021

PPARdelta signaling activation improves metabolic and contractile maturation of human pluripotent stem cell-derived cardiomyocytes.

Pluripotent stem cell-derived cardiomyocytes (PSC-CMs) provide an unprecedented opportunity to study human heart development and disease. A major caveat however is that they remain functionally and structurally immature in culture, limiting their potential for disease modeling and regenerative approaches. Here, we address the question of how different metabolic pathways can be modulated in order to induce efficient hPSC-CM maturation. We show that PPAR signaling acts in an isoform-specific manner to balance glycolysis and fatty acid oxidation (FAO). PPARD activation or inhibition results in efficient respective up- or down-regulation of the gene regulatory networks underlying FAO in hPSC-CMs. PPARD induction further increases mitochondrial and peroxisome content, enhances mitochondrial cristae formation and augments FAO flux. Lastly PPARD activation results in enhanced myofibril organization and improved contractility. Transient lactate exposure, commonly used in hPSC-CM purification protocols, induces an independent program of cardiac maturation, but when combined with PPARD activation equally results in a metabolic switch to FAO. In summary, we identify multiple axes of metabolic modifications of hPSC-CMs and a role for PPARD signaling in inducing the metabolic switch to FAO in hPSC-CMs. Our findings provide new and easily implemented opportunities to generate mature hPSC-CMs for disease modeling and regenerative therapy.

cell biology↗