Associations and dissociations between default and self-reference networks in the human brain.
Neuroimaging has revealed consistent activations in medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC) extending to precuneus both during explicit self-reference tasks and during rest, a period during which some form of self-reference is assumed to occur in the default mode of brain function. The similarity between these two patterns of midline cortical activation may reflect a common neural system for explicit and default-mode self-reference, but there is little direct evidence about the similarities and differences between the neural systems that mediate explicit self-reference versus default-mode self-reference during rest. In two experiments, we compared directly the brain regions activated by explicit self-reference during judgments about trait adjectives and by rest conditions relative to a semantic task without self-reference. Explicit self-reference preferentially engaged dorsal MPFC, rest preferentially engaged precuneus, and both self-reference and rest commonly engaged ventral MPFC and PCC. These findings indicate that there are both associations (shared components) and dissociations between the neural systems underlying explicit self-reference and the default mode of brain function.
Massachusetts Institute of Technology, Department of Brain and Cognitive Sciences, Harvard-MIT Division of Health Sciences and Technology, and Poitras Center for Affective Disorders Research, Cambridge, MA 02139, USA swg@mit.edu
Susan
S
Whitfield-Gabrieli
Joseph M
JM
Moran
Alfonso
A
Nieto-Castañón
Christina
C
Triantafyllou
Rebecca
R
Saxe
John D E
JD
Gabrieli
D000328:Adult; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D004532:Ego; D006801:Humans; D008279:Magnetic Resonance Imaging; D009415:Nerve Net / Q000502:physiology*; D012649:Self Concept