From hidden springs to endless oceans: exploring the complementary roles of the amygdala and hippocampus in...

Current theories of consciousness often emphasize its ego-centric functions, highlighting the role of the insular cortex in interoceptive self-modeling and subcortical brain regions in qualitative experience and motivation, aptly described as the 'hidden spring' of consciousness. From ecological and pragmatic perspectives, conscious experience may facilitate the self-organization of complex organisms by optimizing goals that are typically parallel, multifaceted, and difficult to reconcile. However, the notion that all forms of conscious experience are ego-centric, or at least grounded in a minimal sense of self, is challenged by credible reports of minimal phenomenal experience (MPE), which occur without any self-referential content. I propose that this apparent duality in conscious experience can be explained by the dual-origin theory of cortical development. This theory suggests a gradual expansion of cortical cytoarchitecture from two distinct subcortical origins. The 'Amygdala-System' supports interoceptive self-modeling for habitual interactions with the body and the environment. It expands ventrally from the olfactory system and amygdala, enabling ego-centric processing. In contrast, the 'Hippocampus-System', centered on the hippocampus and expanding dorsally, supports allocentric cognition and experiences that are not constrained by self-referential processing. This complementary system allows for open-ended, selfless forms of experience, akin to an 'endless ocean'. In this framework, MPE may represent a fragile form of consciousness, typically overshadowed by the self-related interoceptive and exteroceptive functions of the Amygdala-System. Finally, I discuss how real-time functional magnetic resonance imaging (fMRI) neurofeedback could be used to upregulate the Hippocampus-System, potentially enabling the controlled study of MPE in neuroscientific settings.