Neurobiology of self-awareness deficits in schizophrenia: A hypothetical model.

Self-awareness (SA) is a cognitive ability to differentiate between self and non-self cues and is pivotal to understand the behavior of other human beings. For this reason, there has been a significant interest to investigate the neurobiology of SA in human subjects. So far the majority of such research has been conducted in healthy subjects but a significant relationship between impaired SA and poor psychosocial outcome in schizophrenia has stimulated neuroimaging research in this patient population. The results from small number of neuroimaging studies in schizophrenia suggest that impaired SA may be mediated by a dysfunction of cortical midline structures. This paper is an attempt to review emerging functional magnetic resonance imaging (fMRI) data in schizophrenia and to propose a hypothetical model of deficits in SA in schizophrenia that can be tested in future research. The model is refined from the available literature and proposes that self-referential activity appears to reflect a shift from activation of anterior to posterior cortical midline structures in schizophrenia subjects, which may be related to lack of functional connectivity between different cortical midline regions.