Human experience, bodily states, and insula

Insula plays a key role in experiential components of human behavior, both in its affective, embodied and cognitive aspects. It is critically implicated in many types of behavior, such as pain, disgust, fear and anxiety, but also pleasure, addiction and gambling, empathy and decision making, in both normal and clinical or psychopathological conditions. In recent years, research has provided robust evidence supporting the hub function of insula in dynamically integrating affective and bodily aspects of the inner and outer environments. This dovetails with the notion that the body, i.e. the flesh, is a major foundation for many if not all of human experiences. However, the picture emerging from the variety of data on insular functioning is still confusing. For instance, there remains uncertainties and contradictions about functional differences between subdivisions (e.g. anterior and posterior) within the insula, as well as the importance of intra- and inter-individual variability factors in driving insular activity. On the other hand, the growing amount of data poses new challenges for theoretical and applied neuroscience, including the need to replace concepts and models based on local circuits dedicated to single functions, with more comprehensive frameworks suitable for understanding integrated large-scale systems. Far from being clarified, the role of bodily functions in human conscious and nonconscious experience and its relation to insular engagement remain challenging issues. Considering the increasing data gathered with multiple methodologies and growing interest for functional network properties, it appears timely to gather the current knowledge at our disposal and outline new hypotheses about the pervasive insula engagements. Therefore, we propose three dimensions along which research can be organized in the Research Topic and cover the dynamic interactions between insula and human experience:


1. the role of the insula in shaping experience and, vice versa, the role of experience in shaping insula activity, for example, how different contexts and life history can modulate an anxious response or sensitivity to bodily states;


2. how bodily and internal visceral states drive human behaviors and, vice versa, also represent the outcome of behaviors. For example, distinctive bodily states may result passively from exposure to aversive events or deviations from expectations, but also be elicited purposefully as a way of managing pathological feelings of emptiness and leading to drug addiction, gambling, or self-injured behaviors.


3. The nature and impact of individual differences on insula properties and reactivity, ranging from affective to drug responses, including epigenetic perspectives.


Doing so, the Research Topic will also attempt to address and delineate some of the open questions and areas of opportunity that discoveries in neuroscience have contributed to related questions in psychology, psychiatry, medicine, and philosophy. Ultimately, an integrative view of these issues will pave the way for novel clinical applications and shed new light on the effective management of physical and psychological symptoms in various illnesses as well as in medically unexplained symptoms.