Deeper into dissociative Amnesia: A perspective from Higher-Order theories of consciousness

Abstract

Memory is a fundamental brain function relying on complex neurological mechanisms that involve the processes of experiencing, encoding, consolidating and retrieving. A disorder primarily characterized by the loss of (autobiographical) memory owing to stressful or traumatic events is dissociative amnesia, the underlying mechanisms of which are poorly understood and further research is warranted. In this review, we first outline the memory systems and associated brain areas, then introduce the neural suppression pathways of memory retrieval and discuss the neural correlates and influential theoretical models of dissociative amnesia. After reviewing notable consciousness theories, we finally examine dissociative amnesia through the lens of higher-order theories of consciousness. We propose a theoretical model, the metarepresentational system of memory suppression which learns, through self-organizing processes, to downregulate or block access to a negatively colored autobiographical content. More specifically, we hypothesize that dissociative amnesia, primarily addressing some of its selective forms, may emerge from a functional disconnect between first-order representations, located in the neocortex and hippocampus and higher-order representations, the metarepresentations, located in the dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (DLPFC) which evaluate and regulate conscious access. Additionally, we discuss that the inhibitory mechanisms in the metarepresentational system are flexible and dynamic and can reverse the suppression given the appropriate conditions, as seen in actual dissociative amnesia cases. Although empirical evidence is needed to support our theory, we suggest that disruptions in conscious access, such as those seen in dissociative amnesia, offer a powerful window into the broader mechanisms of consciousness.