Psychophysiological and behavioral correlates of interoception: comparing typical and atypical patterns across various organs

Understanding and interpreting our internal signals, known as interoception, is crucial for our survival and directs our behavior and thoughts in daily life. Various gaps in current research in interoception led to the development of this thesis. In Chapter 1, the interoceptive literature was reviewed in depth, including: the various approaches to the study of interoception, including behavioral tasks and self-reported questionnaires across different modalities; the methodologies used to manipulate interoceptive signals; the need for a deeper comprehension of interoception's role in physical disorders seemingly unrelated to it, such as hypertension. Chapter 1 delves into defining interoception as a multimodal construct, acknowledging its variability across different methodologies, particularly behavioral tasks and self-reported questionnaires. It also underscores the potential discrepancies in individuals' abilities concerning specific organs, such as the heart, lungs, and stomach. Chapter 2 proposes to validate a novel bodily illusion, termed the Embreathment Illusion, utilizing both interoceptive and exteroceptive signals within a female sample. In addition, the role of breath in bodily awareness is explored in a female sample and the relationship between menstrual cycle, interoception and body image is investigated. Chapter 3 and Chapter 4 focus on investigating the modulation of interoceptive abilities by employing two distinct neuromodulation techniques: altering cardiac interoception through transcranial magnetic theta burst stimulation and modifying perception of gastric signals via transcutaneous auricular vagus nerve stimulation. Chapter 5 explores the contribution of interoception in Borderline Hypertension, examining the intricate relationship between pain, blood pressure, and the capacity to perceive internal signals. Lastly, the potential applications of these studies for clinical purposes are discussed in Chapter 6.