What does neurovascular coupling describe in the brain?

• A. The relationship between neuronal activity and cerebral blood flow; increased activity increases local blood flow through autoregulation and metabolic signaling.
• B. The process of neuron death due to lack of oxygen.
• C. The myelination pattern of axons during development.
• D. The reabsorption of CSF into venous sinuses.

Answer: (A)

Neurovascular coupling is the link between neural activity and local cerebral blood flow. When neurons become more active, their energy needs rise, so they rely on a rapid, targeted vascular response to supply oxygen and glucose. Neurons and nearby supporting cells release signaling molecules that cause nearby arterioles and capillaries to dilate, increasing blood flow to that specific area—a process called functional hyperemia. This activity-driven vascular change ensures the active brain region gets more blood and aligns with metabolic demand; it also underlies the signals seen in functional imaging like fMRI. Autoregulation helps keep overall blood flow stable, but the essence here is that neural activity directly drives a local vascular response through metabolic signaling. The other options describe different brain processes—neuron death from hypoxia, myelination patterns, and CSF reabsorption—that don’t capture this coupling between activity and blood flow.