Increased neural response related to neutral faces in individuals at risk for psychosis.
ABSTRACT The reliable discrimination of emotional expressions in faces is essential for adequate social interaction. Deficits in facial emotion processing are an important impairment in schizophrenia with major consequences for social functioning and subjective well-being. Whether neural circuits underlying emotion processing are already altered before illness onset is yet unclear. Investigating neural correlates of emotion processing in individuals clinically at risk for psychosis offers the possibility to examine neural processes unchanged by the manifest disorder and to study trait aspects of emotion dysfunctions.
Twelve subjects clinically at risk for psychosis and 12 matched control subjects participated in this study. fMRI data were acquired during an emotion discrimination task consisting of standardized photographs of faces displaying different emotions (happiness, sadness, anger, fear) as well as faces with neutral facial expression.
There were no group differences in behavioral performance. Emotion discrimination was associated with hyperactivations in high-risk subjects in the right lingual and fusiform gyrus as well as the left middle occipital gyrus. Further, high-risk compared to control subjects exhibited stronger activation related to neutral faces relative to emotional faces in the inferior and superior frontal gyri, the cuneus, the thalamus and the hippocampus.
The present study indicates that individuals clinically at risk for psychosis show differences in brain activation associated with processing of emotional and--more pronounced--neutral facial expressions despite an adequate behavioral performance. The proneness to attribute salience to neutral stimuli might indicate a biological risk marker for psychosis.
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ABSTRACT: Schizophrenia is characterized by dysfunctions in neural circuits that can be investigated with electrophysiological methods, such as EEG and MEG. In the present human study, we examined event-related fields (ERFs), in a sample of medication-naive, first-episode schizophrenia (FE-ScZ) patients (n = 14) and healthy control participants (n = 17) during perception of Mooney faces to investigate the integrity of neuromagnetic responses and their experience-dependent modification. ERF responses were analyzed for M100, M170, and M250 components at the sensor and source levels. In addition, we analyzed peak latency and adaptation effects due to stimulus repetition. FE-ScZ patients were characterized by significantly impaired sensory processing, as indicated by a reduced discrimination index (A'). At the sensor level, M100 and M170 responses in FE-ScZ were within the normal range, whereas the M250 response was impaired. However, source localization revealed widespread elevated activity for M100 and M170 in FE-ScZ and delayed peak latencies for the M100 and M250 responses. In addition, M170 source activity in FE-ScZ was not modulated by stimulus repetitions. The present findings suggest that neural circuits in FE-ScZ may be characterized by a disturbed balance between excitation and inhibition that could lead to a failure to gate information flow and abnormal spreading of activity, which is compatible with dysfunctional glutamatergic neurotransmission.Journal of Neuroscience 04/2014; 34(17):5909-17. · 6.75 Impact Factor
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ABSTRACT: The objective of this research is to abstract the differences of the brain functional reaction in mental states by using coherence analysis in electroencephalography (EEG). Twenty-two healthy subjects were assessed for their psychosomatic states using the Cornell Medical Index (CMI) and were divided into two groups: normal (I) and preneurotic (II-IV). The EEG was measured during emotional tasks (relaxed, pleasant, and unpleasant sessions) using audio-visual stimuli and was analyzed using coherence analysis. The coherence values of the preneurotic group in the θ band in 120 s to 150 s of the pleasant and unpleasant sessions and in the β band in the relaxed session were significantly larger than the values of the normal group. The coherence values of the normal and preneurotic groups in the α2 band in 30 s to 60 s and 90 s to 120 s in the unpleasant sessions were significantly larger than the values in the relaxed session. The increase in θ activity suggests that an intuitive and irrational response to the emotional situation would appear, and the β activity indicates that attention would be paid more to external than to internal situations in the preneurotic group. The alpha activity shows that the mentally internal response to the unpleasant situation would be prompt in the normal group, while in contrast the response would be delayed in the preneurotic group. These results suggest that the information processing of emotional stimuli in the brain differ depending on the mental state.Electronics and Communications in Japan 08/2014; 97(8). · 0.18 Impact Factor
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ABSTRACT: Patients with chronic schizophrenia are characterized by deficits in identifying facial expressions of emotion, and these deficits relate to impaired social and occupational function. It is not yet known if these deficits are trait-like and present at the onset of psychosis, preceding a subsequent diagnosis of schizophrenia. Our objective was to systematically review and analyze the extant literature to assess if there is a consistent profile of emotion identification problems in early-onset and first-episode psychosis.Schizophrenia Research 08/2014; · 4.43 Impact Factor