Neurobiology of insight deficits in schizophrenia: An fMRI study

Abstract

Prior research has shown insight deficits in schizophrenia to be associated with specific neuroimaging changes (primarily structural) especially in the prefrontal sub-regions. However, little is known about the functional correlates of impaired insight. Seventeen patients with schizophrenia (mean age 40.0±10.3; M/F= 14/3) underwent fMRI on a Philips 3.0 T Achieva system while performing on a self-awareness task containing self- vs. other-directed sentence stimuli. SPM5 was used to process the imaging data. Preprocessing consisted of realignment, coregistration, and normalization, and smoothing. A regression analysis was used to examine the relationship between brain activation in response to self-directed versus other-directed sentence stimuli and average scores on behavioral measures of awareness of symptoms and attribution of symptoms to the illness from Scale to Assess Unawareness of Mental Disorders. Family Wise Error correction was employed in the fMRI analysis. Average scores on awareness of symptoms (1 = aware; 5 = unaware) were associated with activation of multiple brain regions, including prefrontal, parietal and limbic areas as well as basal ganglia. However, average scores on correct attribution of symptoms (1 = attribute; 5 = misattribute) were associated with relatively more localized activation of prefrontal cortex and basal ganglia. These findings suggest that unawareness and misattribution of symptoms may have different neurobiological basis in schizophrenia. While symptom unawareness may be a function of a more complex brain network, symptom misattribution may be mediated by specific brain regions.

Insight in schizophrenia spectrum disorders: relationship with behavior, mood and perceived quality of life, underlying causes and emerging treatments

“…Consistent with this, studies employing both structural 99 and functional [100][101][102][103][104][105] neuroimaging have implicated a number of areas and networks in the development and maintenance of insight.…”

“…Structural neuroimaging studies have linked poor insight to reduced volume in several areas, including frontal 104,106,107 , temporal 107,108 , parietal 104,107 and occipital 107 regions, the thalamus 101 , basal ganglia 104 and cerebellum 107 , in both first-episode psychosis 109 and chronic schizophrenia 107 .…”

“…In terms of functional imaging studies, converging evidence has now linked poor insight to activity in central midline structures, including basal ganglia 104 , prefrontal cortex 103,104,[115][116][117] , cingulate cortex 103 , insula 117 , inferior parietal lobule 103 and the precuneus 116 . Functional resting state studies also suggest that insight may be related to the default mode network, particularly in the left hemisphere 102 .…”

Symptom attribution and frontal cortical thickness in first‐episode schizophrenia

“…In keeping with the conceptual differentiation between insight domains, results from structural and more recently functional magnetic resonance imaging (fMRI) studies suggest that somewhat distinct neurobiological dysfunction may subserve deficits in each insight dimension. In contrast to the widespread network of brain areas implicated in other insight domains, functional neuroimaging studies describe fewer and more specific frontal areas involved in symptom misattribution, which may indicate a failure to recruit compensatory brain mechanisms …”

Neurobiology of Consciousness: Current Research and Perspectives

“…For example U. Neisser distinguish between five aspects of self -ecological, interpersonal, extended, private and conceptual [87], while S. Gallagher focuses on the distinctions between "minimal self" and "narrative self" as well as on differences between the sense of self-agency and the sense of self-ownership [48]. The complexity of self-consciousness is also taken into account in psychological analyses [34], [64] or research on some diseases [5], [53], [113], [114]. A lot of effort has been put in recent years into investigating the importance of bodily self-consciousness (the pre-reflective and non-conceptual representation of body-related information) for the model of self-consciousness.…”