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Using gaze information to orient attention and guide behavior is critical to social adaptation. Previous studies have suggested that abnormal gaze perception in schizophrenia (SCZ) may originate in abnormal early attentional and perceptual processes and may be related to paranoid symptoms. Using event-related brain potentials (ERPs), this study investigated altered early attentional and perceptual processes during gaze perception and their relationship to paranoid delusions in SCZ. Twenty-eight individuals with SCZ or schizoaffective disorder and 32 demographically matched healthy controls (HCs) completed a gaze-discrimination task with face stimuli varying in gaze direction (direct, averted), head orientation (forward, deviated), and emotion (neutral, fearful). ERPs were recorded during the task. Participants rated experienced threat from each face after the task. Participants with SCZ were as accurate as, though slower than, HCs on the task. Participants with SCZ displayed enlarged N170 responses over the left hemisphere to averted gaze presented in fearful relative to neutral faces, indicating a heightened encoding sensitivity to faces signaling external threat. This abnormality was correlated with increased perceived threat and paranoid delusions. Participants with SCZ also showed a reduction of N170 modulation by head orientation (normally increased amplitude to deviated faces relative to forward faces), suggesting less integration of contextual cues of head orientation in gaze perception. The psychophysiological deviations observed during gaze discrimination in SCZ underscore the role of early attentional and perceptual abnormalities in social information processing and paranoid symptoms of SCZ., ((c) 2015 APA, all rights reserved).)

Schizophrenia remains a major burden on patients and society. The dopamine hypothesis attempts to explain the pathogenic mechanisms of the disorder, and the neurodevelopmental hypothesis the origins. In the past 10 years an alternative, the cognitive model, has gained popularity. However, the first two theories have not been satisfactorily integrated, and the most influential iteration of the cognitive model makes no mention of dopamine, neurodevelopment, or indeed the brain. In this Review we show that developmental alterations secondary to variant genes, early hazards to the brain, and childhood adversity sensitise the dopamine system, and result in excessive presynaptic dopamine synthesis and release. Social adversity biases the cognitive schema that the individual uses to interpret experiences towards paranoid interpretations. Subsequent stress results in dysregulated dopamine release, causing the misattribution of salience to stimuli, which are then misinterpreted by the biased cognitive processes. The resulting paranoia and hallucinations in turn cause further stress, and eventually repeated dopamine dysregulation hardwires the psychotic beliefs. Finally, we consider the implications of this model for understanding and treatment of schizophrenia., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

A previous study suggests that the amplitude of the N400 event-related potentials (ERPs) of healthy subjects does not vary with their delusional-like ideations. This contrasts with the smaller N400 amplitudes observed in more- than in less-deluded schizophrenia patients. Here, we hypothesize that these smaller N400 amplitudes were related to the paranoid feelings patients had during the ERP recording. We thus induced this type of feelings in healthy subjects. Delusional-like ideation was assessed with the schizotypal personality questionnaire. Thirty-four healthy subjects completed a semantic categorization task. Paranoid feelings were significantly enhanced by the induction. In these conditions, greater delusional-like ideation scores were associated with smaller N400 amplitudes and larger late positive components. Controlling for the two other schizotypal factors strengthened these results. These findings may help us understand why delusions persist., (Copyright © 2010 Society for Psychophysiological Research.)

This study aimed to explore the validity of an experiment-based paradigm for assessing the suspicious thoughts in healthy volunteers and its corresponding neural process. Twenty-four pairs of healthy college students participated in this study and were randomly assigned to two experimental conditions: the informed (12 pairs) and the naive (12 pairs) conditions. EEG of one subject in each pair was recorded when the 'feeling of being seen through' was evoked. The findings showed a prominent positive deflection of the difference wave within the time window 200 ms-400 ms after stimuli presentation (0 ms) in the naive group. The ERP amplitude of frontal and central scalp sites was significantly different between high and low paranoia rating scores. These findings provide preliminary evidence on the use of an ERP paradigm to detect paranoid ideation or suspicious thoughts in non-clinical sample.

Background: People with persecutory delusions regard ambiguous data in the social domain as self-relevant and selectively attend to threatening information. This study aimed to characterize these social cognitive biases in functional neuroanatomical terms., Method: Eight schizophrenic patients with active persecutory delusions and eight matched normal controls underwent functional magnetic resonance imaging while determining the self-relevance of ambiguous self-relevant or unambiguous other-relevant neutral and threatening statements., Results: In determining self-relevance, the deluded subjects showed a marked absence of rostral-ventral anterior cingulate activation together with increased posterior cingulate gyrus activation in comparison to the normal subjects. The influence of threat on self-relevance determination did not yield statistically significant differences between deluded and normal subjects., Conclusions: Abnormalities of cingulate gyrus activation while determining self-relevance suggest impaired self-reflection in the persecutory deluded state. This may contribute to persecutory belief formation and maintenance.

Twenty schizophrenia-like psychotic patients suspected of epilepsy were explored using EEG techniques (recordings in the 10-20 International System, source derivation, EEG mapping and EEG spectral reaction mapping by photic and somesthetic stimulation). In 16 of them, latent epileptic disorders were found. EEG spiking foci could be located either: (a) in temporal, (b) fronto-basal, or (3) in the sagittal-line leads. A corresponding associated dysrhythmia was clearly revealed by EEG mapping. On EEG spectral reaction mapping a suggestive aberrant displacement of the area of maximal sensory response was found. These EEG disorders were in significant relation with the psychotic syndrome observed in the respective group of patients: (a) patients with fronto-basal (temporal anterior) foci were prevalently paranoid; (b) patients with temporal lobe foci were prevalently depressive; (c) patients with sagittal line (singular) foci presented a predominantly expansive, hypomanic behaviour. The study shows the importance of normal fronto-limbic circuits for the preservation of mental health.

Evidence from psychophysiological and behavioral investigations of lateralization in psychosis separates two clinical syndromes. A speculative model is offered in which the syndromes approximate the clinical features of paranoid compared with nonparanoid patients in investigations in which the groups have been distinguished in the psychology laboratory (Magaro 1980), and encompass the distinction between acute functional psychoses and classical schizophrenia (Kety 1980). A parsimonious account is provided of the hemispheric imbalances of function tht underpin the syndromes.