Me, Myself and My Insula: An Oasis in the Forefront of Self-Consciousness

SIMPLE SUMMARY: The insula, or the fifth lobe of the brain, is involved in a wide variety of functions, including processes related to the self. The self is a complex construct comprising both a subjective–objective dimension and a temporal dimension. However, because of the lack of direct investigation, it remains unclear the way the insula is involved in the different aspects of the self. This review describes the insula from both an anatomical and a functional point of view, the self through its different dimensions and the way the insula is involved in the self, relying on studies in healthy controls and in various affections. Understanding the link between the insula and the self might lead to improvement in care provision. ABSTRACT: The insula is a multiconnected brain region that centralizes a wide range of information, from the most internal bodily states, such as interoception, to high-order processes, such as knowledge about oneself. Therefore, the insula would be a core region involved in the self networks. Over the past decades, the question of the self has been extensively explored, highlighting differences in the descriptions of the various components but also similarities in the global structure of the self. Indeed, most of the researchers consider that the self comprises a phenomenological part and a conceptual part, in the present moment or extending over time. However, the anatomical substrates of the self, and more specifically the link between the insula and the self, remain unclear. We conducted a narrative review to better understand the relationship between the insula and the self and how anatomical and functional damages to the insular cortex can impact the self in various conditions. Our work revealed that the insula is involved in the most primitive levels of the present self and could consequently impact the self extended in time, namely autobiographical memory. Across different pathologies, we propose that insular damage could engender a global collapse of the self.