Neural oscillations dissociate between self-related attentional orientation versus evaluation.

To investigate whether self-reflection on personality traits engages distinct neural mechanisms of self-related attentional orientation and self-related evaluation, we recorded electroencephalograms from adults while they made trait judgments about themselves and an age- and gender-matched friend, or judgments of word valence. Each trial consisted of a cue word that indicated a target person for trait judgment or instructed valence judgment, followed by a trait adjective to be evaluated. Using a wavelet analysis, we calculated time-frequency power at each electrode and phase synchrony between electrode pairs associated with self-, friend- or valence-cues and with trait adjectives during trait or valence judgments. Relative to friend- and valence-cues, self-cues elicited increased synchronous activity in delta (2-4Hz), theta (5-7Hz), alpha (8-13Hz), beta (14-26Hz), and gamma (28-40Hz) bands, and increased large-scale phase synchrony in these frequency bands. Self-related evaluation compared to friend-related evaluation during trait judgments induced stronger desynchronization in alpha, beta and gamma band activities, and decreased phase synchrony in alpha and gamma band activities. Our findings suggest that self-related attentional orientation and self-related evaluation engage distinct neural mechanisms that are respectively characterized by synchrony and desynchrony of neural activity in local assemblies and between long-distance brain regions.