Encyclopedia of Autism Spectrum Disorders

2013 Edition
| Editors: Fred R. Volkmar

Blood-Oxygen-Level-Dependent (BOLD) Signal

  • Kevin A. PelphreyEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4419-1698-3_550



Blood-oxygen-level-dependent (BOLD) signal is the magnetic resonance imaging (MRI) contrast of blood deoxyhemoglobin. Seiji Ogawa and his colleagues first discovered this intrinsic contrast mechanism in 1990. Neurons do not store internal reserves of glucose and oxygen, which are essential to their proper function. Increases in neuronal activity, typically in response to a demand for information processing, require more glucose and oxygen to be rapidly delivered via the blood stream. Via this hemodynamic response, blood releases glucose and oxygen to active neurons at a faster rate relative to inactive neurons. This results in a surplus of oxyhemoglobin localized to the active area, giving rise to a measureable change in the local ration of oxy- to deoxyhemoglobin, thus providing a localizable marker of activity for MRI.

See Also

References and Readings

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  3. Ogawa, S., Lee, T. M., Nayak, A. S., & Glynn, P. (1990). Oxygenation-sensitive contrast in magnetic resonance image of rodent brain at high magnetic fields. Magnetic Resonance in Medicine, 14, 68–78.PubMedGoogle Scholar

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© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.Child Study CenterYale University School of MedicineNew HavenUSA