Altered attentional and perceptual processes as indexed by N170 during gaze perception in schizophrenia: Relationship with perceived threat and paranoid delusions

Characteristics of Cognitive Event-Related Potential Components and N170 Source Analysis in Patients with Acute Cerebellar Infarction

This study aims to evaluate cognitive impairments in patients with acute cerebellar infarction using event-related potentials (ERP) and electrophysiological source imaging (ESI). Thirty patients with acute cerebellar infarction and 32 healthy volunteers were selected. Cognitive potentials were recorded and measured using a visual Oddball paradigm. Source analysis of the N170 component was performed using standardized low-resolution brain electromagnetic tomography (sLORETA) to compare the standardized current density distribution between the two groups under different stimuli. For inverted and upright face stimuli, the amplitudes of N170, VPP, and N300 in the patient group were significantly lower than those in the control group (p < 0.05). For upright house stimuli, the VPP amplitude in the patient group was also lower than that in the control group (p < 0.05). Source analysis revealed that the brain regions with significant differences between the acute cerebellar infarction group and the control group included the temporal and parietal lobes. Specifically, activation in the precuneus was reduced during inverted face stimuli; activation in the middle temporal gyrus was reduced during upright face stimuli; and activation in the middle temporal gyrus and fusiform gyrus was increased during both inverted and upright house stimuli. Patients with acute cerebellar infarction exhibit abnormal P100, N170/VPP, and N300 amplitudes. Source analysis of the N170 component revealed altered activation in the middle and inferior temporal gyri, fusiform gyrus, middle occipital gyrus, and precuneus, which play a role in selective cognitive impairments following cerebellar infarction.

Could an evaluative conditioning intervention ameliorate paranoid beliefs? Self-reported and neurophysiological evidence from a brief intervention focused on improving self-esteem

Introduction

Much research on the treatment of paranoia has involved cognitive-behavioural interventions that address explicit social cognition processes. However, much of human cognition is preverbal or implicit, raising the possibility that such social judgements are implicated in paranoia. One type of implicit social cognition that has been investigated concerning paranoia is implicit self-esteem with some evidence that it may be possible to change implicit self-esteem using techniques based on conditioning theory. Therefore, the primary purpose of this research is to further evaluate the potential of this approach. At the same time, as a secondary purpose, we introduce a novel way of measuring social cognition that, we argue, has utility for investigating the psychological processes involved in paranoia.

Method

We conducted two proof-of-concept studies of a novel brief intervention based on evaluative conditioning, targeting implicit cognition. The first study was conducted with a large non-clinical sample, while the second study included a small series of psychotic patients. As part of our proof-of-concept evaluation of the potential of evaluative conditioning, we attempted to probe for neurophysiological changes following the intervention using magnetoencephalography in an exploratory way in the clinical sample.

Results

Our results revealed that both non-clinical and clinical participants in the experimental group showed a significant change in how they evaluated themselves in the social cognition task, which could be related to the perception of social information in a less threatening way. In addition, clinical participants in the experimental group showed changes in brain activity during the social cognition task, particularly in regions involved in emotional reactivity and mentalization processes.

Discussion

Our results are encouraging, suggesting that implicit cognition is manipulable, that such manipulation affects underlying neurophysiological mechanisms, and that there may be an impact on paranoid symptoms. However, much more work is required to determine whether this approach can produce meaningful clinical change and be delivered in routine clinical settings. Finally, it is important to note that we are not claiming the clinical effectiveness of our intervention, which is in a very early stage of development. Our goal here is to demonstrate clinical possibilities that warrant further investigation.

Cognitive Mechanisms of Aberrant Self-Referential Social Perception in Psychosis and Bipolar Disorder: Insights From Computational Modeling

BACKGROUND AND HYPOTHESIS

Individuals with schizophrenia (SZ) and bipolar disorder (BD) show disruptions in self-referential gaze perception-a social perceptual process related to symptoms and functioning. However, our current mechanistic understanding of these dysfunctions and relationships is imprecise.

STUDY DESIGN

The present study used mathematical modeling to uncover cognitive processes driving gaze perception abnormalities in SZ and BD, and how they relate to cognition, symptoms, and social functioning. We modeled the behavior of 28 SZ, 38 BD, and 34 controls (HC) in a self-referential gaze perception task using drift-diffusion models parameterized to index key cognitive components: drift rate (evidence accumulation efficiency), drift bias (perceptual bias), start point (expectation bias), threshold separation (response caution), and nondecision time (encoding/motor processes).

STUDY RESULTS

Results revealed that aberrant gaze perception in SZ and BD was driven by less efficient evidence accumulation, perceptual biases predisposing self-referential responses, and greater caution (SZ only). Across SZ and HC, poorer social functioning was related to greater expectation biases. Within SZ, perceptual and expectancy biases were associated with hallucination and delusion severity, respectively.

CONCLUSIONS

These findings indicate that diminished evidence accumulation and perceptual biases may underlie altered gaze perception in patients and that SZ may engage in compensatory cautiousness, sacrificing response speed to preserve accuracy. Moreover, biases at the belief and perceptual levels may relate to symptoms and functioning. Computational modeling can, therefore, be used to achieve a more nuanced, cognitive process-level understanding of the mechanisms of social cognitive difficulties, including gaze perception, in individuals with SZ and BD.

Cognitive Mechanisms of Aberrant Self-Referential Social Perception in Psychosis and Bipolar Disorder: Insights from Computational Modeling

Background and Hypothesis

Individuals with schizophrenia (SZ) and bipolar disorder (BD) show disruptions in self-referential gaze perception-a social perceptual process related to symptoms and functioning. However, our current mechanistic understanding of these dysfunctions and relationships is imprecise.

Study Design

The present study used mathematical modeling to uncover cognitive processes driving gaze perception abnormalities in SZ and BD, and how they relate to cognition, symptoms, and social functioning. We modeled the behavior of 28 SZ, 38 BD, and 34 controls (HC) in a self-referential gaze perception task using drift-diffusion models (DDM) parameterized to index key cognitive components: drift rate (evidence accumulation efficiency), drift bias (perceptual bias), start point (expectation bias), threshold separation (response caution), and non- decision time (encoding/motor processes).

Study Results

Results revealed that aberrant gaze perception in SZ and BD was driven by less efficient evidence accumulation, perceptual biases predisposing self-referential responses, and greater caution (SZ only). Across SZ and HC, poorer social functioning was related to greater expectation biases. Within SZ, perceptual and expectancy biases were associated with hallucination and delusion severity, respectively.

Conclusions

These findings indicate that diminished evidence accumulation and perceptual biases may underlie altered gaze perception in patients and that SZ may engage in compensatory cautiousness, sacrificing response speed to preserve accuracy. Moreover, biases at the belief and perceptual levels may relate to symptoms and functioning. Computational modeling can, therefore, be used to achieve a more nuanced, cognitive process-level understanding of the mechanisms of social cognitive difficulties, including gaze perception, in individuals with SZ and BD.

An ERP Study of Face Processing in Schizophrenia, Bipolar Disorder, and Socially Isolated Individuals from the Community

People with schizophrenia (SCZ) and bipolar disorder (BD) have impairments in processing social information, including faces. The neural correlates of face processing are widely studied with the N170 ERP component. However, it is unclear whether N170 deficits reflect neural abnormalities associated with these clinical conditions or differences in social environments. The goal of this study was to determine whether N170 deficits would still be present in SCZ and BD when compared with socially isolated community members. Participants included 66 people with SCZ, 37 with BD, and 125 community members (76 "Community-Isolated"; 49 "Community-Connected"). Electroencephalography was recorded during a face processing task in which participants identified the gender of a face, the emotion of a face (angry, happy, neutral), or the number of stories in a building. We examined group differences in the N170 face effect (greater amplitudes for faces vs buildings) and the N170 emotion effect (greater amplitudes for emotional vs neutral expressions). Groups significantly differed in levels of social isolation (Community-Isolated > SCZ > BD = Community-Connected). SCZ participants had significantly reduced N170 amplitudes to faces compared with both community groups, which did not differ from each other. The BD group was intermediate and did not differ from any group. There were no significant group differences in the processing of specific emotional facial expressions. The N170 is abnormal in SCZ even when compared to socially isolated community members. Hence, the N170 seems to reflect a social processing impairment in SCZ that is separate from level of social isolation.

The effects of abnormal visual experience on neurodevelopmental disorders

Normal visual development is supported by intrinsic neurobiological mechanisms and by appropriate stimulation from the environment, both of which facilitate the maturation of visual functions. However, an offset of this balance can give rise to visual disorders. Therefore, understanding the factors that support normal vision during development and in the mature brain is important, as vision guides movement, enables social interaction, and allows children to recognize and understand their environment. In this paper, we review fundamental mechanisms that support the maturation of visual functions and discuss and draw links between the perceptual and neurobiological impairments in autism spectrum disorder (ASD) and schizophrenia. We aim to explore how this is evident in the case of ASD, and how perceptual and neurobiological deficits further degrade social ability. Furthermore, we describe the altered perceptual experience of those with schizophrenia and evaluate theories of the underlying neural deficits that alter perception.

Reductions in regional theta power and fronto-parietal theta-gamma phase-amplitude coupling during gaze processing in bipolar disorder

Impaired social cognition is common in bipolar disorder (BD) and predicts poor functional outcomes. A critical determinant of social cognition is the ability to discriminate others' gaze direction, and its alteration may contribute to functional impairment in BD. However, the neural mechanisms underlying gaze processing in BD are unclear. Because neural oscillations are crucial neurobiological mechanisms supporting cognition, we aimed to understand their role in gaze processing in BD. Using electroencephalography (EEG) data recorded during a gaze discrimination task for 38 BD and 34 controls (HC), we examined: theta and gamma power over bilateral posterior and midline anterior locations associated with early face processing and higher-level cognitive processing, and theta-gamma phase-amplitude coupling (PAC) between locations. Compared to HC, BD showed reduced midline-anterior and left-posterior theta power, and diminished bottom-up/top-down theta-gamma PAC between anterior/posterior sites. Reduced theta power and theta-gamma PAC related to slower response times. These findings suggest that altered theta oscillations and anterior-posterior cross-frequency coupling between areas associated with higher-level cognition and early face processing may underlie impaired gaze processing in BD. This is a crucial step towards translational research that may inform novel social cognitive interventions (e.g., neuromodulation to target specific oscillatory dynamics) to improve functioning in BD.

Electrophysiological Studies of Reception of Facial Communication in Autism Spectrum Disorder and Schizophrenia

Autism spectrum disorder (ASD) and schizophrenia spectrum disorders (SZ) are characterized by difficulty with social cognition and atypical reception of facial communication - a key area in the Research Domain Criteria framework. To identify areas of overlap and dissociation between ASD and SZ, we review studies of event-related potentials (ERP) to faces across ASD and SZ populations, focusing on ERPs implicated in social perception: P100, N170, N250, and P300. There were many inconsistent findings across studies; however, replication was strongest for delayed N170 latency in ASD and attenuated N170 amplitude in SZ. These results highlight the challenges of replicating research findings in heterogeneous clinical populations and the need for transdiagnostic research that continuously quantifies behavior and neural activity across neurodevelopmental disorders.

Neural Oscillatory Abnormalities During Gaze Processing in Schizophrenia: Evidence of Reduced Theta Phase Consistency and Inter-areal Theta-Gamma Coupling

BACKGROUND

Abnormal gaze discrimination in schizophrenia (SZ) is associated with impairment in social functioning, but the neural mechanisms remain unclear. Evidence suggests that local neural oscillations and inter-areal communication through neural synchronization are critical physiological mechanisms supporting basic and complex cognitive processes. The roles of these mechanisms in abnormal gaze processing in SZ have not been investigated. The present study examined local neural oscillations and connectivity between anterior and bilateral posterior brain areas during gaze processing.

METHODS

During electroencephalography recording, 28 participants with SZ and 34 healthy control participants completed a gaze discrimination task. Time-frequency decomposition of electroencephalography data was used to examine neural oscillatory power and intertrial phase consistency at bilateral posterior and midline anterior scalp sites. In addition, connectivity between these anterior and posterior sites, in terms of cross-frequency coupling between theta phase and gamma amplitude, was examined using the Kullback-Leibler Modulation Index.

RESULTS

Participants with SZ showed reduced total power of theta-band activity relative to healthy control participants at all sites examined. This group difference could be accounted for by reduced intertrial phase consistency of theta activity in SZ participants, which was related to reduced gaze discrimination accuracy in SZ. In addition, SZ participants exhibited reduced Kullback-Leibler indexing, both feedforward and feedback connectivity, between the posterior and anterior sites.

CONCLUSIONS

These findings suggest that abnormal theta phase consistency and dysconnection between posterior face processing and anterior areas may underlie gaze processing deficits in SZ.

The attenuated visual scanpaths of patients with schizophrenia whilst recognizing emotional facial expressions are worsened in natural social scenes

Alteration of visual scanpaths under emotional facial expression in schizophrenia patients has been described in recent years; however, it is not clear whether such results are different when they transfer to faces in natural social scenes. The present study was designed to investigate the effects of emotional faces in natural social scenes on the gaze patterns of patients with schizophrenia, compared to gaze at isolated faces. A novel theme identification task was used where participants selected a positive, neutral or negative word to describe an emotional picture. Participants were 29 patients with schizophrenia and 31 healthy controls. The Positive and Negative Syndrome Scale (PANSS) and the Scale of Social Function in Psychosis Inpatients (SSPI) were used to assess symptoms and social functioning. In total, patients with schizophrenia showed significantly fewer fixations, saccades numbers and decreased fixations in areas of interest. As expected, patients showed shorter scanpath length, but only in the pictures with social settings. Furthermore, the effect size of scanpaths parameters under social scene was all greater than isolated face. In addition, patients compared to controls showed more abnormal scanpath parameters processing negative and neutral faces than positive faces, especially in social scene. The present study suggests that scanpath length for social scene faces may be more sensitive than for isolated face pictures. Our findings further support restricted scanpath whilst recognizing emotional facial expressions in natural social scenes as a favorable topic for further investigation as a trait marker.

Risk perception in paranoia and anxiety: Two investigations across clinical and non-clinical populations

Objectives

It is common, among clinical and non-clinical populations alike, for paranoia and anxiety to co-occur. It has been suggested that anxiety and its related appraisal styles may contribute to development of paranoia. We aimed to evaluate different aspects of risk perception in relation to paranoia and anxiety and to identify specific aspects that may differentiate paranoia from anxiety. This paper consists of two inter-related studies.

Methods

Study 1 compared 30 patients with persecutory delusions, 21 patients with generalized anxiety disorder and 52 healthy controls. Study 2 compared 30 non-clinical individuals with high levels of paranoia and anxiety, 28 individuals with high anxiety only and 36 healthy controls. Within each study, the two symptomatic groups were matched on level of anxiety. Four dimensions of risk perception (i.e. likelihood, harm, controllability, and intentionality) were compared across groups, as measured by the locally validated Risk Perception Questionnaire.

Results

In both studies, the paranoia and the anxiety groups reported an elevated perceived likelihood of negative events than controls respectively. Only the paranoia groups reported an elevated perceived harm of neutral events than controls. In Study 2, the two at-risk groups attributed more harm and intentionality to negative events than controls.

Conclusion

Although perception of negative events was characteristic in anxiety (with or without paranoia), a biased perception of neutral events as risky was unique to the addition of paranoia. Implications to the transdiagnostic and continual view of psychopathology, and mechanism-based interventions were discussed.

Altered N170 and mood symptoms in bipolar disorder: An electrophysiological study of configural face processing

OBJECTIVES

Altered social behavior during mood episodes in bipolar disorder often has detrimental and long-lasting interpersonal consequences. Abnormal face processing may play a role in linking brain functions to clinical symptoms and behavior. This study aimed to understand configural face processing in bipolar disorder as a function of basic communicative attributes of the face and mood symptoms using event-related brain potentials (ERPs).

METHODS

Forty-two participants with bipolar I disorder (BP) and 43 healthy controls (HC) viewed face stimuli varying in emotion (neutral or fearful), head orientation (forward or deviated), and gaze direction (direct or averted) while ERPs were recorded. Configural face processing was indexed by the N170 wave.

RESULTS

BP participants had comparable overall N170 amplitude and peak latency to HC, although timing was more variable in the BP group. Abnormal N170 modulations by communicative face attributes were observed in BP: exaggerated sensitivity to emotion (fearful > neutral) in the left hemisphere, and reduced sensitivity to gaze-head incongruency (where N170 is normally larger in response to faces with incongruent than congruent gaze and head direction) in the right hemisphere. The former was not associated with mood symptoms, suggesting a heightened trait-like sensitivity to negative emotions. The latter was correlated with greater manic symptoms, indicating that an impaired perceptual sensitivity to faces with features signaling incongruent social attention may underlie social deficits observed during mania.

CONCLUSIONS

These findings suggest a pathophysiological role of altered configural face processing in the phenomenology of bipolar disorder, and call for further investigations to evaluate its potential as a biomarker and treatment target.

Deficient cortical face-sensitive N170 responses and basic visual processing in schizophrenia

BACKGROUND

Face detection, an ability to identify a visual stimulus as a face, is impaired in patients with schizophrenia. It is unclear whether impaired face processing in this psychiatric disorder results from face-specific domains or stems from more basic visual domains. In this study, we examined cortical face-sensitive N170 response in schizophrenia, taking into account deficient basic visual contrast processing.

METHODS

We equalized visual contrast signals among patients (n=20) and controls (n=20) and between face and tree images, based on their individual perceptual capacities (determined using psychophysical methods). We measured N170, a putative temporal marker of face processing, during face detection and tree detection.

RESULTS

In controls, N170 amplitudes were significantly greater for faces than trees across all three visual contrast levels tested (perceptual threshold, two times perceptual threshold and 100%). In patients, however, N170 amplitudes did not differ between faces and trees, indicating diminished face selectivity (indexed by the differential responses to face vs. tree).

CONCLUSION

These results indicate a lack of face-selectivity in temporal responses of brain machinery putatively responsible for face processing in schizophrenia. This neuroimaging finding suggests that face-specific processing is compromised in this psychiatric disorder.