Pre-reflective and reflective self-reference: a spatiotemporal EEG analysis.

Functional imaging studies consistently support the role of the medial prefrontal cortex to be a part of a functional network of reflective self-awareness. The current study introduces a new linguistic task which (1) directly compares self-reference and other-reference, and (2) separates pre-reflective from reflective aspects of self-awareness. Twenty-six healthy volunteers evaluated trait adjectives in reference to the self or a close friend while a continuous 30-channel EEG was recorded. Low-resolution brain electromagnetic tomography (LORETA) was used for statistical brain imaging. As expected, the direct comparison of self-reference to other-reference revealed the MPFC to be significant and strongly more active during the self-reference condition. Pre-reflective aspects of self seem to be implemented to a greater degree in the ventral, reflective aspects of the self in dorsal parts of the MPFC. In the pre-reflective self condition, brain areas that receive homeostatic afferents from somatic and visceral sensation of the body such as the insula and the somatosensory cortex were strongly activated as early as 134 ms after stimulus onset. The right inferior parietal lobe seems to be involved in self-referential processing in general.