Theory of mind in schizophrenia: exploring neural mechanisms of belief attribution.
ABSTRACT Although previous behavioral studies have shown that schizophrenia patients have impaired theory of mind (ToM), the neural mechanisms associated with this impairment are poorly understood. This study aimed to identify the neural mechanisms of ToM in schizophrenia, using functional magnetic resonance imaging (fMRI) with a belief attribution task.
In the scanner, 12 schizophrenia patients and 13 healthy control subjects performed the belief attribution task with three conditions: a false belief condition, a false photograph condition, and a simple reading condition.
For the false belief versus simple reading conditions, schizophrenia patients showed reduced neural activation in areas including the temporoparietal junction (TPJ) and medial prefrontal cortex (MPFC) compared with controls. Further, during the false belief versus false photograph conditions, we observed increased activations in the TPJ and the MPFC in healthy controls, but not in schizophrenia patients. For the false photograph versus simple reading condition, both groups showed comparable neural activations.
Schizophrenia patients showed reduced task-related activation in the TPJ and the MPFC during the false belief condition compared with controls, but not for the false photograph condition. This pattern suggests that reduced activation in these regions is associated with, and specific to, impaired ToM in schizophrenia.
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ABSTRACT: Background: Deficits in the capacity to reflect about the self and others (“social reflection” [SR]) have been iden- tified in schizophrenia, as well as in people with a genetic or clinical risk for the disorder. However, the neural underpinnings of these abnormalities are incompletely understood. Methods: Responses of a network of brain regions known to be involved in self and other processing (e.g., medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC), and superior temporal gyrus (STG)) were measured during SR in 16 first-degree, non-psychotic relatives (RELS) of schizophrenia patients and 16 healthy con- trols (CONS). Because of prior evidence linking dysfunction in this network and delusions, associations be- tween SR-related responses of this network and subclinical delusions (measured using the Peters et al. Delusions Inventory) were also examined. Results: Compared with CONS, RELS showed significantly less SR-related activity of the right and left PCC and STG. Moreover, response magnitudes were negatively correlated with levels of delusional thinking across both groups. Conclusions: These findings suggest that aberrant function of the neural circuitry underpinning SR is asso- ciated with the genetic liability to schizophrenia and confers vulnerability to delusional beliefs.Schizophrenia Research 08/2014; In Press(1-3). DOI:10.1016/j.schres.2014.05.033 · 4.43 Impact Factor
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ABSTRACT: The aim of this study was to investigate the influence of neurocognition on affective and cognitive theory of mind (ToM) tasks in early phases of psychosis. In a cross-sectional study of 60 first-episode schizophrenia/schizoaffective disorder patients, the implication of neurocognition in first- and second-order ToM stories, Hinting Task, and Reading the Mind in the Eyes Test (RMET) was analyzed. Regression models were used, controlling for clinical symptoms and antipsychotic dose. Spatial span backward (odds ratio [OR], 0.34; p = 0.01) and intrusions in the Rey Auditory Verbal Learning Test (OR, 4.86; p = 0.04) were the best factors to predict second-order ToM failure. Trail Making Test B (B = 0.01; p = 0.04) and negative symptoms (B = 0.09; p = 0.01) predicted Hinting task performance while Block design (B = 0.1; p = 0.04) was related to RMET outcome. Executive functions and clinical symptoms were related to ToM performance in first-episode schizophrenia patients, although different patterns of relationship were observed in each ToM task.Journal of Nervous & Mental Disease 07/2014; 202(8). DOI:10.1097/NMD.0000000000000164 · 1.81 Impact Factor
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ABSTRACT: We performed a quantitative meta-analysis of functional neuroimaging studies to identify brain areas which are commonly engaged in social and visuo-spatial perspective taking. Specifically, we compared brain activation for visual-perspective taking to activation for false belief reasoning, which requires awareness of perspective to understand someone's mistaken belief about the world which contrasts with reality. In support of a previous account by Perner and Leekam (2008), our meta-analytic conjunction analysis found common activation for false belief reasoning and visual perspective taking in the left but not the right dorsal temporo-parietal junction (TPJ). This fits with the idea that the left dorsal TPJ is responsible for representing different perspectives in a domain-general fashion. Moreover, our conjunction analysis found activation in the precuneus and the left middle occipital gyrus close to the putative Extrastriate Body Area (EBA). The precuneus is linked to mental-imagery which may aid in the construction of a different perspective. The EBA may be engaged due to imagined body-transformations when another's viewpoint is adopted.Frontiers in Human Neuroscience 01/2013; 7:712. DOI:10.3389/fnhum.2013.00712 · 2.90 Impact Factor