The following is my understanding, but I could be wrong:
When neurons activate, they release a neurotransmitter (typically glutamate) that then binds to nearby astrocytes. Astrocytes then increase their intracellular calcium levels which in turn causes vascular dilation of the nearby area, thus increasing blood flow to that area.
When neurons activate, they release a neurotransmitter (typically glutamate) that then binds to nearby astrocytes. Astrocytes then increase their intracellular calcium levels which in turn causes vascular dilation of the nearby area, thus increasing blood flow to that area.