Neurovascular Coupling in Functional Imaging

Neurovascular coupling describes the cascade of cellular and molecular events by which changes in neuronal activity elicit local adjustments in cerebral blood flow and volume. This relationship underpins the interpretation of functional magnetic resonance imaging (fMRI) signals, particularly the blood oxygenation level-dependent (BOLD) contrast, which reflects dynamic shifts in oxy- and deoxyhaemoglobin. At the cellular level, excitatory and inhibitory neurons, astrocytes and vascular cells communicate via neurotransmitters, nitric oxide, prostanoids and neuropeptides to orchestrate vasodilation or vasoconstriction. Advances in optical, ultrasound and hybrid imaging platforms have enhanced spatiotemporal resolution, permitting single-vessel mapping of haemodynamic parameters alongside direct measures of neuronal activity. Greater understanding of cell-type specificity, neurochemical modulation and brain-state dependence has revealed both positive and negative BOLD responses, underscoring the need to integrate multimodal readouts when studying healthy function and pathology. The global significance of this field spans basic neuroscience, clinical neuroimaging and translational research, with implications for interpreting brain connectivity, diagnosing cerebrovascular disorders and guiding therapeutic interventions.

Research from Nature Portfolio

Recent studies have extended our knowledge of regional and cell-type contributions to fMRI signals. A 2024 investigation into the striatum demonstrated that optogenetic activation of specific afferents can evoke negative BOLD responses through vasoconstriction, despite elevated neuronal firing. This effect is mediated by opioidergic signalling and is recapitulated in human experiments, emphasising the role of vasoactive neurotransmission in shaping fMRI polarity. A foundational multimodal study combined two-photon microscopy, fast ultrasound and BOLD-fMRI within the same experimental preparation to compare microscopic capillary dilation with mesoscopic blood-volume maps during sensory stimulation. It revealed that functional hyperaemia occurs at the threshold of neuronal activation and that vascular signals scale linearly with local calcium dynamics, thereby clarifying the limits and correspondence of different imaging scales.

Neurovascular Coupling in Functional Imaging publication trend

The graph below shows the total number of articles in neurovascular coupling in functional imaging across all publications each year (not limited to Nature Index journals).

Technical terms

Neurovascular coupling: Mechanism linking neuronal activity to changes in cerebral blood flow and volume.

BOLD signal: Blood oxygenation level-dependent contrast in fMRI reflecting oxygenated haemoglobin changes.

Cerebral blood flow (CBF): Rate of blood delivery to brain tissue, typically measured in mL per 100 g per minute.

Cerebral blood volume (CBV): Volume of blood within a given brain region, influencing haemodynamic response.

Optogenetics: Technique using light to control genetically sensitised neurons and modulate vascular responses.

References

1. Distinct neurochemical influences on fMRI response polarity in the striatum. Nature Communications (2024).
2. Mesoscopic and microscopic imaging of sensory responses in the same animal. Nature Communications (2019).
3. Multiparametric Brain Hemodynamics Imaging Using a Combined Ultrafast Ultrasound and Photoacoustic System. Advanced Science (2024).
4. Cortex-wide neural dynamics predict behavioral states and provide a neural basis for resting-state dynamic functional connectivity. Cell Reports (2023).
5. Cell type specificity of neurovascular coupling in cerebral cortex. eLife (2016).