A default mode of brain function
Marcus E. Raichle, Ann Mary MacLeod, Abraham Z. Snyder, William J. Powers, Debra A. Gusnard, Gordon L. Shulman
Proceedings of the National Academy of Sciences January 16, 2001 DOI: 10.1073/pnas.98.2.676 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Population | Normal adult human brain |
| Topics | Default mode network |
| Keywords | Human brain Baseline sea Resting State FMRI Positron emission tomography Electroencephalography |
| Citations | 12,440 |
| Key findings | The oxygen extraction fraction is remarkably uniform across the awake, resting brain, and all significant deviations from this baseline are deactivations, primarily in the visual system, suggesting a default mode of brain function. |
Abstract
A baseline or control state is fundamental to the understanding of most complex systems. Defining a baseline state in the human brain, arguably our most complex system, poses a particular challenge. Many suspect that left unconstrained, its activity will vary unpredictably. Despite this prediction we identify a baseline state of the normal adult human brain in terms of the brain oxygen extraction fraction or OEF. The OEF is defined as the ratio of oxygen used by the brain to oxygen delivered by flowing blood and is remarkably uniform in the awake but resting state (e.g., lying quietly with eyes closed). Local deviations in the OEF represent the physiological basis of signals of changes in neuronal activity obtained with functional MRI during a wide variety of human behaviors. We used quantitative metabolic and circulatory measurements from positron-emission tomography to obtain the OEF regionally throughout the brain. Areas of activation were conspicuous by their absence. All significant deviations from the mean hemisphere OEF were increases, signifying deactivations, and resided almost exclusively in the visual system. Defining the baseline state of an area in this manner attaches meaning to a group of areas that consistently exhibit decreases from this baseline, during a wide variety of goal-directed behaviors monitored with positron-emission tomography and functional MRI. These decreases suggest the existence of an organized, baseline default mode of brain function that is suspended during specific goal-directed behaviors.
In the evidence
This study is part of the evidence base for a synthesis in the library. Here is how each one recorded it.
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Oxygen extraction fraction was uniform in the resting brain, with significant deviations being deactivations mainly in the visual system, supporting a baseline default mode of brain function.
Synthesized
Comparable studies
Other observational and cohort studies on default mode network, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Resting-State Functional Connectivity Reflects Structural Connectivity in the Default Mode Network Healthy subjects | 2008 | Observational cohort | |
| Meditation experience is associated with increased cortical thickness Participants with extensive Insight meditation experience and matched controls | 2005 | Observational cohort | n = 20 |
| Meditation experience is associated with differences in default mode network activity and connectivity Experienced meditators and matched meditation-naive controls | 2011 | Observational cohort | |
| The precuneus/posterior cingulate cortex plays a pivotal role in the default mode network: Evidence from a partial correlation network analysis Healthy subjects | 2008 | Observational study | |
| The salience network is responsible for switching between the default mode network and the central executive network: Replication from DCM Healthy subjects | 2014 | Observational study |
Citations in the library
Cited by 785
- The Brain's Default Mode Network Annual Review of Neuroscience May 4, 2015
- Resting-State Functional Connectivity Reflects Structural Connectivity in the Default Mode Network Cerebral Cortex April 9, 2008
- Experience sampling during fMRI reveals default network and executive system contributions to mind wandering. Proceedings of the National Academy of Sciences May 26, 2009
- Default Mode Network Activity and Connectivity in Psychopathology Annual Review of Clinical Psychology March 29, 2012
- Meditation experience is associated with differences in default mode network activity and connectivity Proceedings of the National Academy of Sciences November 23, 2011
and 780 more in the library