The brain is a heterogeneous organ with regionally varied and constantly changing energetic needs. Blood vessels in the brain are equipped with control mechanisms that match oxygen and glucose delivery through blood flow with the local metabolic demands that are imposed by neural activity. However, the cellular bases of this mechanism have remained elusive. A major advance has been the demonstration that astrocytes, cells with extensive contacts with both synapses and cerebral blood vessels, participate in the increases in flow evoked by synaptic activity. Their organization in nonoverlapping spatial domains indicates that they are uniquely positioned to shape the spatial distribution of the vascular responses that are evoked by neural activity. Astrocytic calcium is an important determinant of microvascular function and may regulate flow independently of synaptic activity. The involvement of astrocytes in neurovascular coupling has broad implications for the interpretation of functional imaging signals and for the understanding of brain diseases that are associated with neurovascular dysfunction.
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T. Takano and J. Pierce provided invaluable help with the figures. This work was supported by grants from the US National Institutes of Health (NS37853 and HL18974 to C.I., and NS56188 and NS50315 to M.N.).
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Iadecola, C., Nedergaard, M. Glial regulation of the cerebral microvasculature. Nat Neurosci 10, 1369–1376 (2007). https://doi.org/10.1038/nn2003
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