Consistency and functional specialization in the default mode brain network.
The notion of a "default mode of brain function" has taken on certain relevance in human neuroimaging studies and in relation to a network of lateral parietal and midline cortical regions that show prominent activity fluctuations during passive imaging states, such as rest. In this study, we perform three fMRI experiments that demonstrate consistency and specialization in the default mode network. Correlated activity fluctuations of default mode network regions are identified during (i) eyes-closed spontaneous rest, (ii) activation by moral dilemma, and (iii) deactivation by Stroop task performance. Across these imaging states, striking uniformity is shown in the basic anatomy of the default mode network, but with both tasks clearly and differentially modulating this activity compared with spontaneous fluctuations of the network at rest. Against rest, moral dilemma is further shown to evoke regionally specific activity increases of hypothesized functional relevance. Mapping spontaneous and task-related brain activity will help to constrain the meaning of the default mode network. These findings are discussed in relation to recent debate on the topic of default modes of brain function.
Harrison
Ben J
BJ
Institut d'Alta Tecnologia-Parc de Recerca Biomèdica de Barcelona, CRC Corporació Sanitària, 08003 Barcelona, Spain. habj@unimelb.edu.au
Pujol
Jesus
J
López-Solà
Marina
M
Hernández-Ribas
Rosa
R
Deus
Joan
J
Ortiz
Hector
H
Soriano-Mas
Carles
C
Yücel
Murat
M
Pantelis
Christos
C
Cardoner
Narcís
N
D001288:Attention; D001931:Brain Mapping; D002540:Cerebral Cortex; D006801:Humans; D008279:Magnetic Resonance Imaging; D008606:Mental Processes / Q000502:physiology*; D009014:Morals; D009434:Neural Pathways / Q000502:physiology*; D012146:Rest; D013647:Task Performance and Analysis