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BOLD signal
Also written as: BOLD — blood oxygen level-dependent
Blood oxygen level-dependent signal changes that indicate neural activity in fMRI.
Full Definition
Blood oxygen level-dependent (BOLD) signal refers to the hemodynamic response measured in functional MRI that reflects changes in blood oxygenation associated with neural activity. When neurons become active, they consume oxygen, leading to increased blood flow to that brain region. This creates measurable signal changes that serve as an indirect marker of brain function, though the BOLD response occurs 4-6 seconds after the actual neural activity.
Usage
Usage note: BOLD is always capitalized when referring to the signal; spell out on first use.
In Context
- "The BOLD signal showed a typical hemodynamic response function peaking at 6 seconds post-stimulus." — fMRI analysis report
- "Caffeine consumption can significantly alter BOLD signal amplitude and timing." — Study protocol guidelines
Also known as
blood oxygen level-dependent signal
hemodynamic response
Don't confuse with
neural signal
electrical activity