When we smell hot dogs, it may trigger memories of backyard barbeques or attending baseball games during childhood. During this process, the areas of the brain that control smell and long-term memory are rapidly firing off impulses. To fuel these signals from neurons, the active brain regions need oxygen and energy in the form of blood sugar glucose, which is quickly delivered through blood vessels.
Click here for original story, Special vascular cells adjust blood flow in brain capillaries based on local energy needs
Source: Phys.org