Emotional Face Perception in Patients with Schizophrenia: an Event-Related Potential Study

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.

Neurophysiological substrates of configural face perception in schizotypy

Face perception is a highly developed function of the human visual system. Previous studies of event-related potentials (ERPs) have identified a face-selective ERP component (negative peak at about 170 ms after stimulus onset, N170) in healthy participants. In contrast, patients with schizophrenia exhibit reduced amplitude of the N170, which may represent a pathological deficit in the neurophysiology of face perception. Interestingly, healthy humans with schizophrenia-like experiences (schizotypy) also exhibit abnormal processing of face perception. Yet, it has remained unknown how schizotypy in healthy humans is associated with the neurophysiological substrates of face perception. Here, we recruited 35 healthy participants and assessed their schizotypy by the magical ideation rating scale. We used high-density electroencephalography to obtain ERPs elicited by a set of Mooney faces (face and non-face visual stimuli). We investigated median and mean reaction times and visual ERP components in response to the stimuli. We observed a significant difference in N170 amplitude between the two face-stimulus conditions and found that the measured schizotypy scores were significantly correlated with both reaction times and N170 amplitude in response to the face stimuli across all participants. Our results thus support the model of schizotypy as a manifestation of a continuum between healthy individuals and patients with schizophrenia, where the N170 impairment serves as a biomarker for the degree of pathology along this continuum.

Neutral face and complex object neurophysiological processing deficits in long-term schizophrenia and in first hospitalized schizophrenia-spectrum individuals

BACKGROUND

Face processing is impaired in long-term schizophrenia as indexed by a reduced face-related N170 event-related potential (ERP) that corresponds with volumetric decreases in right fusiform gyrus. Impairment in face processing may constitute an object-specific deficit in schizophrenia that relates to social impairment and misattribution of social signs in the disease, or the face deficit may be part of a more general deficit in complex visual processing. Further, it is not clear the degree to which face and complex object processing deficits are present early in disease course. To that end, the current study investigated face- and object-elicited N170 in long-term schizophrenia and the first hospitalized schizophrenia-spectrum.

METHODS

ERPs were collected from 32 long-term schizophrenia patients and 32 matched controls, and from 31 first hospitalization patients and 31 matched controls. Subjects detected rarely presented butterflies among non-target neutral faces and automobiles.

RESULTS

For both patient groups, the N170s to all stimuli were significantly attenuated. Despite this overall reduction, the increase in N170 amplitude to faces was intact in both patient samples. Symptoms were not correlated with N170 amplitude or latency to faces.

CONCLUSIONS

Information processing of complex stimuli is fundamentally impaired in schizophrenia, as reflected in attenuated N170 ERPs in both first hospitalized and long-term patients. This suggests the presence of low-level visual complex object processing deficits near disease onset that persist with disease course.

Impairments of emotional face processing in schizophrenia patients: Evidence from P100, N170 and P300 ERP components in a sample of auditory hallucinators

Patients with schizophrenia show impaired face and emotional expression processing that may be due to early perceptual deficits or late impairments in higher-order emotional facial recognition. This study examined event-related potentials (ERPs) in 23 patients with schizophrenia who experience auditory hallucinations and 19 healthy controls. EEG activity was recorded from 32 scalp sites positioned according to the 10-10 placement system. Linked left and right electrodes at the mastoids served as the reference. The P100, N170 and P300 were measured during an emotional facial identification task, which included neutral, joyful, sad, angry and fearful facial expressions and non-face stimuli (chairs). P100 was measured at O_1/2 and P_7/8. N170 was measured at P_7/8. P300 was measured at P_z. Patients with schizophrenia were slower at identifying all facial expressions, including neutral ones. They also showed less positive P100 amplitude to sad, angry and fearful facial expressions. N170 amplitudes were smaller in patients in response to neutral, joyful, sad, angry, and fearful facial expression. Patients showed less positive P300 mean amplitudes to all facial expressions, including neutral ones. Within-group comparisons showed that patients exhibited a different pattern of ERP modulation across facial expressions than controls for P100 and N170, but not for P300. Our findings are compatible with the idea that behavioural and electrophysiological face-processing deficits in schizophrenia arise from early-stage deficits in visual processing.

Considerations in biomarker development for neurodevelopmental disorders

PURPOSE OF REVIEW

Despite significant progress in recognizing the biological bases of autism spectrum disorder, diagnosis and treatment rely primarily on subjective evaluation of behavior. This review highlights the challenges unique to neurodevelopmental disorders that have limited biomarker development.

RECENT FINDINGS

The field of neurodevelopmental disorders requires objective quantification of biological processes to enable designation of subgroups likely to benefit from specific treatments, index diagnostic status/risk, demonstrate engagement of targeted systems, and provide more rapid assessment of change than traditional clinical observation and caregiver report measures.

SUMMARY

Useful biomarkers for neurodevelopmental disorders must be reliable across development, evident at the individual level, and specific to a unit of analysis, be it diagnostic status or functional process. The ultimate value of biomarkers for neurodevelopmental disorders will relate to their ease of use, cost, scalability, sensitivity, and methodological objectivity.

The effect of ketamine on configural facial processing

Ketamine can induce a transient psychosis via its influence on ionotropic N-methyl-d-aspartate receptors. Unlike dopamine agonists, which specifically mimic the positive symptoms seen in psychotic illnesses such as schizophrenia, ketamine may provide a better model because it is able to induce not only positive symptoms but also schizophrenia-like cognitive and negative symptoms. To test the veracity of the ketamine model further, research is attempting to replicate a range of cognitive deficits associated with schizophrenia in healthy controls under the influence of ketamine. Facial processing is one area that is impaired in schizophrenia. More specifically, research suggests that schizophrenia is associated with a reduced facial inversion effect reflecting abnormalities in configural face processing. The purpose of the current study was to determine whether ketamine would also reduce the facial inversion effect. This study was a double-blind, placebo-controlled repeated-measures design in which data are presented for 14 participants who received ketamine on one occasion and saline on another. The results supported the ketamine model, with the participants demonstrating an intact inversion effect in the placebo condition but no inversion effect under the influence of ketamine. Further, participants' self-reported deficits in visual processing correlated with their inversion score and errors on the faces task. Future studies should examine a wider range of facial processing tasks with a larger sample to confirm the current results and to determine the specificity of ketamine's ability to mimic schizophrenia facial processing deficits. The current study is supportive of the role of glutamate system in the processing of configural face information.

Face recognition in schizophrenia disorder: A comprehensive review of behavioral, neuroimaging and neurophysiological studies

Facial emotion processing has been extensively studied in schizophrenia patients while general face processing has received less attention. The already published reviews do not address the current scientific literature in a complete manner. Therefore, here we tried to answer some questions that remain to be clarified, particularly: are the non-emotional aspects of facial processing in fact impaired in schizophrenia patients? At the behavioral level, our key conclusions are that visual perception deficit in schizophrenia patients: are not specific to faces; are most often present when the cognitive (e.g. attention) and perceptual demands of the tasks are important; and seems to worsen with the illness chronification. Although, currently evidence suggests impaired second order configural processing, more studies are necessary to determine whether or not holistic processing is impaired in schizophrenia patients. Neural and neurophysiological evidence suggests impaired earlier levels of visual processing, which might involve the deficits in interaction of the magnocellular and parvocellular pathways impacting on further processing. These deficits seem to be present even before the disorder out-set. Although evidence suggests that this deficit may be not specific to faces, further evidence on this question is necessary, in particularly more ecological studies including context and body processing.

Meta-analysis of face processing event-related potentials in schizophrenia

BACKGROUND

Schizophrenia is associated with impaired face processing. N170 and N250 are two event-related potentials that have been studied in relation to face processing in schizophrenia, but the results have been mixed. The aim of this article was to conduct a meta-analysis of N170 and N250 in schizophrenia to evaluate trends and resolve the inconsistencies.

METHODS

Twenty-one studies of N170 (n = 438 schizophrenia patients, n = 418 control subjects) and six studies of N250 (n = 149 schizophrenia patients, n = 151 control subjects) were evaluated. Hedges' g was calculated for each study, and the overall weighted mean effect size (ES) was calculated for N170 and N250. Homogeneity of the ES distributions, potential publication bias, and impact of potential moderators were also assessed.

RESULTS

The amplitude of both N170 and N250 to face stimuli was smaller in patients than control subjects (N170 ES = .64; N250 ES = .49; ps < .001). The distributions of the ES were homogeneous (ps > .90), and there was no indication of a publication bias. We found no significant effect of task requirements regarding judgments of the face stimuli. Moreover, we found no significant difference between the ES for N170 and N250.

CONCLUSIONS

Though findings of individual studies have been mixed, the results of the meta-analysis strongly support disruption of N170 and N250 in schizophrenia. The comparable effect sizes across the two waveforms suggest that the well-established behavioral deficit in face emotion processing is mirrored in an underlying neural impairment for processing faces.