Processing of emotional words under distinct awareness conditions: analysis of spatiotemporal pattern of event-related potential

Abstract

Objective To investigate the mechanism of neural processing of emotional words under distinct awareness conditions using spatiotemporal pattern of event-related potentials (ERP). Methods The ERPs were recorded in 11 healthy subjects while they performed a task of perceptual judgement on facial photograph gender, which were arrayed behind emotional words. Word valence was an implicit processing factor. The 2 (consciousness: awareness, unawareness)×2 (positive/neutral, negative/neutral) factorial design of repeated-measure was applied to utilize the difference wave between emotional word under distinct awareness conditions. The analysis results were revealed by the statistical parametric mapping (SPM) of F value resulting from repeated measurement ANOVA. Results The SPM of F-value suggested significant interaction effect between awareness and word valence in left frontal-temporal areas and right occipital regions (60-80 ms). The significant awareness effects occurred separately in bilateral frontal-partial and right temporal regions (110-150 ms). The significant emotion effects occurred in left and right extensive cerebral hemisphere regions (60-90 ms). Conclusion The spatiotemporal patterns of ERPs suggest the underlying mechanisms are that the emotional words processing of both unawareness and awareness might involve the same neural modules in earlier period.The former decreases the strength of those neural assemblies' activation than the latter. Either positive or negative words can activate left cerebral hemisphere simultaneously with right cerebral hemisphere. Key words: Event-related potentials; Awareness; Emotion words; Spatiotemporal patternanalysis