neurovascular coupling
The physiological relationship between neural activity and local cerebral blood flow changes that underlies functional neuroimaging signals.
Full Definition
Neurovascular coupling refers to the complex physiological mechanism by which increases in neural activity trigger corresponding increases in local cerebral blood flow, blood volume, and oxygen delivery. This coupling forms the biological foundation for functional neuroimaging techniques including fMRI, which detect these hemodynamic changes as surrogates for neural activity. The coupling involves intricate interactions between neurons, astrocytes, and vascular smooth muscle cells, with typical response delays of 2-6 seconds following neural activation. Understanding neurovascular coupling is essential for interpreting functional imaging results, as pathological conditions such as stroke, aging, or vascular disease can alter this relationship and affect the reliability of activation maps.
Usage
Usage note: Use consistently with 'neurovascular' as one word; avoid hyphenated forms except when used as a compound modifier.
In Context
- "Impaired neurovascular coupling in the patient's stroke-affected hemisphere may compromise the reliability of functional activation maps." — Functional MRI interpretation report
- "The study protocol must account for age-related changes in neurovascular coupling when comparing activation patterns across patient groups." — Research imaging protocol