Blood-Oxygen-Level-Dependent (BOLD) Signal

How a region's shifting balance of oxygenated to deoxygenated blood, driven by increased neural activity, can be detected magnetically rather than electrically.

References

• Ogawa, S., Lee, T.M., Kay, A.R., Tank, D.W. "Brain Magnetic Resonance Imaging with Contrast Dependent on Blood Oxygenation." PNAS 87, no. 24 (1990): 9868–9872.