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: 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; · 1.84 Impact Factor
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ABSTRACT: Indirect evidence suggests partially common pathogenetic mechanisms for Neurological Soft Signs (NSS), neurocognition, and social cognition in schizophrenia. However, the possible association between NSS and mentalizing impairments has not yet been examined. In the present study, we assessed the ability to attribute mental states to others in patients with schizophrenia and predicted that the presence of theory of mind deficits would be significantly related to NSS. Participants were 90 clinically stable patients with a DSM-IV diagnosis of schizophrenia. NSS were assessed using the Neurological Evaluation Scale (NES). Theory of mind deficits were assessed using short verbal stories designed to measure false belief understanding. The findings of the study confirmed our hypothesis. Impaired sequencing of complex motor acts was the only neurological abnormality correlated with theory of mind deficits. By contrast, sensory integration, motor coordination and the NES Others subscale had no association with patients׳ ability to pass first- or second-order false belief tasks. If confirmed by future studies, the current findings provide the first preliminary evidence for the claim that specific NSS and theory of mind deficits may reflect overlapping neural substrates.Psychiatry research. 04/2014;
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ABSTRACT: We meta-analyzed imaging studies on theory of mind and formed individual task groups based on stimuli and instructions. Overlap in brain activation between all task groups was found in the mPFC and in the bilateral posterior TPJ. This supports the idea of a core network for theory of mind that is activated whenever we are reasoning about mental states, irrespective of the task- and stimulus-formats (Mar, 2011). In addition, we found a number of task-related activation differences surrounding this core-network. ROI based analyses show that areas in the TPJ, the mPFC, the precuneus, the temporal lobes and the inferior frontal gyri have distinct profiles of task-related activation. Functional accounts of these areas are reviewed and discussed with respect to our findings.Neuroscience & Biobehavioral Reviews 05/2014; · 10.28 Impact Factor