A default mode of brain function
Marcus Raichle and five colleagues ask how to define a baseline state for the human brain. They use positron-emission tomography to measure the oxygen extraction fraction, the ratio of oxygen used by the brain to oxygen delivered by flowing blood, and find it remarkably uniform in people who are awake and resting with their eyes closed. Areas of activation are conspicuous by their absence, and the only significant deviations are increases in extraction, signifying deactivations, almost all in the visual system. Defining the baseline this way gives meaning to a group of areas that consistently fall below it during a wide variety of goal-directed behaviours monitored with PET and fMRI. The authors suggest an organised, baseline default mode of brain function that is suspended during specific goal-directed behaviours. This page cites the paper for the baseline definition and the name default mode.
Marcus Raichle and five colleagues ask how to define a baseline state for the human brain. They use positron-emission tomography to measure the oxygen extraction fraction, the ratio of oxygen used by the brain to oxygen delivered by flowing blood, and find it remarkably uniform in people who are awake and resting with their eyes closed. Areas of activation are conspicuous by their absence, and the only significant deviations are increases in extraction, signifying deactivations, almost all in the visual system. Defining the baseline this way gives meaning to a group of areas that consistently fall below it during a wide variety of goal-directed behaviours monitored with PET and fMRI. The authors suggest an organised, baseline default mode of brain function that is suspended during specific goal-directed behaviours. This page cites the paper for the baseline definition and the name default mode.
Written from the abstract on PubMed, read 2026-10-23.
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Raichle, M. E., MacLeod, A. M., Snyder, A. Z., Powers, W. J., Gusnard, D. A., & Shulman, G. L. (2001). A default mode of brain function. Proceedings of the National Academy of Sciences, 98(2), 676-682. doi:10.1073/pnas.98.2.676