The multidimensional self and its interplay with emotion processing across the life span

Until today, experts from different disciplines have been struggling to find an answer into the long standing enigma of body and mind, as an effort of incorporating new scientific knowledge into classical philosophical approaches. In specific, there are two distinct aspects that enable the access to our internal and external bodily self: interoception and exteroception. Researchers argue that these two aspects are strongly related, as they interact with each other and shape a holistic perception of human consciousness; hence they form the multimodal self. On one hand, interoception describes how brain receives and integrates endogenous bodily signals, in order to create body’s phenomenological experience and has been found to be pivotal for emotion processing, decision making, understanding psychopathology etc. Various measures are proposed for determining different aspects of interoceptive signaling, leading the way towards new interdisciplinary and innovative research. On the other hand, exteroception is a term strongly related to the concept of embodiment and body ownership; processes or phenomena which contribute into shaping self-awareness, as they emphasize the interaction between sensory motor experience and external perception of the world and can influence emotion awareness, empathy, as well as overall psychological wellbeing. Bearing these in mind, the scope of the present dissertation is the profound understanding of the exact mechanisms underlying interoceptive and exteroceptive signaling through the life span, as well as how these express themselves in clinical conditions. For exploring possible inter-individual differences and mediating/moderating factors, subjective and objective data regarding emotion processing style, emotion recognition, alexithymia but also physical activity and BMI were collected for various populations (primary school children, adolescents and women currently suffering from bulimia nervosa). In specific, electrocardiography and electroencephalography were implemented for quantifying interoceptive accuracy (IAC) and for recording neural electrical activity in emotion face processing. Furthermore, with the help of wearable devices (Actiheart® and Polar watch ®) it was possible to track physical activity and accordingly cardiac circle in daily life. Besides these, the rubber hand illusion experiment was conducted to investigate exteroceptive/proprioceptive processes and subsequently embodiment. Our findings revealed, firstly, a strong interaction between interoceptive signaling and self-regulation of physical activity or fatigue in primary school children, where one’s own limits regarding exhaustion are becoming more defined. Secondly, the importance of physical fitness from early childhood, which can enable the conscious perception and interpretation of internal bodily signals was highlighted. Likewise, facets of interoception were found asymmetrical in patients with bulimia nervosa, indicating normal perception of cardiac activity, but a decreased tendency in being internally focused. Lastly, among adolescents, the regulation of frustration and distress caused by recognizing negative emotions in others, was found to be closely related to interoceptive signaling, whilst alexithymic traits were connected to lower levels of embodiment/exteroception. In conclusion, all these findings help us understand better the importance of the interoceptive and exteroceptive self, which together sculpt the multimodal self. The discussion of these findings focuses on their contribution for shaping cognition and affect and thus describe how they amalgamate in order to shape self-awareness through the life span. In view of that, integrating this important knowledge in prevention programs in schools, as well as in new intervention methods in inpatient and outpatient settings, can be described as highly valuable. Overall there is great need for further research regarding these aspects, as the road ahead of the multimodal self remains long but challenging.