pubmed.ncbi.nlm.nih.gov

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

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

Ivy F Tso et al. J Abnorm Psychol. 2015 Aug.

Abstract

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).

PubMed Disclaimer

Figures

Figure 1
Figure 1

Sample face stimuli of the 8 experimental conditions of the gaze discrimination task.

Figure 2
Figure 2

Procedure of the gaze discrimination task. Each trial consisted of a fixation cross (500 ms), followed by the target face (100 ms) to which participants were allowed up to 2,000 ms to press a button to indicate whether the face was “looking at me” or “looking away from me,” and then a blank screen (1,000 ms). The task consisted of totally 512 trials (64 trials × 8 conditions), presented in a pseudo-randomized order in four blocks with a brief break between blocks.

Figure 3
Figure 3

N170 principle component loadings overlaid on original N170 waveforms of HC and SCZ participants. Shaded area represents the selected N170 time window (148 – 200 ms) based on the criterion of principle component loading ≥ 0.6 (right y-axis). For ERP, negative is plotted upward.

Figure 4
Figure 4

Behavioral results of the gaze discrimination task. Left panels: accuracy. Middle panels: RT. Right panels: perceived threat.

Figure 5
Figure 5

Laterality × Emotion × Gaze × Group interaction: N170 response to averted gaze presented in fearful relative to neutral faces over the left hemisphere was accentuated in SCZ participants. a) Original waveforms at scalp sites P7 (left hemisphere) and P8 (right hemisphere) of SCZ and HC. Shaded area indicates the N170 time window. b) N170 amplitude as represented by mean PCA score, at scalp sites P7 (left) and P8 (right), of SCZ and HC. Error bars depict standard errors of mean. Negative is plotted upward.

Figure 5
Figure 5

Laterality × Emotion × Gaze × Group interaction: N170 response to averted gaze presented in fearful relative to neutral faces over the left hemisphere was accentuated in SCZ participants. a) Original waveforms at scalp sites P7 (left hemisphere) and P8 (right hemisphere) of SCZ and HC. Shaded area indicates the N170 time window. b) N170 amplitude as represented by mean PCA score, at scalp sites P7 (left) and P8 (right), of SCZ and HC. Error bars depict standard errors of mean. Negative is plotted upward.

Figure 6
Figure 6

Correlations of increased N170 amplitude to threat-signaling faces at P7 and P8 scalp sites in SCZ with: a) increased perceived threat to threat-signaling faces, and b) more severe paranoid delusions. Y-axis represents the N170 amplitude difference between averted gaze in fearful faces and averted gaze in neutral faces; positive values indicate larger N170 amplitude to fearful relative to neutral. Ranges in parentheses are 95% confidence interval of the correlation estimates, derived based on 1,000 bootstrap samples.

Figure 7
Figure 7

Head × Group interaction: SCZ participants showed a reduction of head orientation effect on N170 amplitude compared with HC. a) ERP waveforms (average of sites P7 and P8), with shaded area indicating the N170 time window. b) N170 amplitudes as represented by mean PCA scores within the indicated time window. Error bars depict standard errors of mean. Negative is plotted upward.

Similar articles

Cited by

References

    1. Adams RB, Jr, Kleck RE. Effects of direct and averted gaze on the perception of facially communicated emotion. Emotion. 2005;5(1):3. - PubMed
    1. Andreasen NC. Scale for the Assessment of Negative Symptoms (SANS) Iowa City, IA: University of Iowa; 1983.
    1. Andreasen NC. Scale for the Assessment of Positive Symptoms (SAPS) Iowa City, IA: University of Iowa; 1984.
    1. Ashley V, Vuilleumier P, Swick D. Time course and specificity of event-related potentials to emotional expressions. Neuroreport. 2004;15(1):211–216. - PubMed
    1. Batty M, Taylor MJ. Early processing of the six basic facial emotional expressions. Brain Res Cogn Brain Res. 2003;17(3):613–620. - PubMed

Publication types

MeSH terms