Électrophysiologie et vulnérabilité schizophrénique : la composante N400 comme endophénotype candidat ?

Electrophysiological correlates of emotional meaning in context in relation to facets of schizotypal personality traits: A dimensional study

AIMS

The aim of this study was to investigate the neurocognitive processes mediating the processing of emotional information during the integration of contextual and social information in a schizotypal population.

METHODS

One hundred and thirty-one healthy participants were evaluated using the Schizotypal Personality Questionnaire and event-related potentials were recorded during a linguistic task in which participants read sentence pairs describing short social situations to themselves. The first sentence implicitly conveyed the positive or negative emotional state of a character. The second sentence was emotionally congruent or incongruent with the first sentence.

RESULTS

Across our overall sample, our results revealed a greater N400 effect at right sites than left sites, whereas the late positive component effect was only observed at left sites. Concerning the correlation results, we observed a negative link between positive and global schizotypy and N400 modulation in response to congruent targets for positive context sentences. Results also showed a positive correlation between negative schizotypy and late positive component modulation in response to congruent targets for negative context sentences.

CONCLUSIONS

These results suggest that the different facets of the schizotypal personality traits influenced the integration of emotional context at the level of both early and later-mobilized neurocognitive processes.

Haemodynamic and electrophysiological markers of pragmatic language comprehension in schizophrenia

OBJECTIVES

The present study aimed at investigating neurophysiological markers of language perception in schizophrenia using simultaneous near-infrared spectroscopy (NIRS) and event-related potentials (ERPs), which have been proven to be useful for studying language processing abilities in psychiatric patients. The study shall help to integrate previous findings from ERP and fMRI studies on figurative language comprehension in schizophrenia and elucidate how electrophysiological and haemodynamic markers of language processing are related.

METHODS

Twenty-two healthy subjects and 22 schizophrenia patients judged 120 sentences regarding their meaningfulness. Phrases were literal, metaphoric, or meaningless. EEG-fNIRS signals were recorded throughout the entire experiment.

RESULTS

Schizophrenia patients showed deficient and delayed sentence comprehension. Both the early N400 and left-hemispheric activation during language comprehension were altered in patients. Correlation analyses showed that metaphor-related ERPs were strongly linked to haemodynamic cortical activity in healthy subjects, but not in patients.

CONCLUSIONS

Our results indicate group differences in cortical electrophysiological and haemodynamic activation that represent rather general impairments in the processing of complex language. Simultaneous EEG/NIRS applications are useful to depict these neural markers and to investigate their relationship. Future studies are needed to clarify the nature of respective anomalies and their potential as putative neural markers in schizophrenia research.