Haemodynamic response
（重定向自Hemodynamic response）
![The canonical haemodynamic response function. The spike indicates a brief intense period of neuron stimulation, which requires increased blood and nutrient flow. As the needs of the neuronal activity are met, blood flow returns to homeostatic levels.](/Images/godic/202501/17/Haemodynamic_response_function.svg1110.png")
![Brain blood vasculature as a function of blood flow. Red arrows show vascular pruning, while white arrowheads indicate vessel widening in response to increased blood flow.[2]](/Images/godic/202501/17/Brain_blood_vasculature_as_a_function_of_blood_flow_-_journal.pbio.1001375.g0011110.png")
![This sample fMRI shows how there are certain areas of activation during stimulation](/Images/godic/202501/17/FMRI1111.jpg")
In haemodynamics, the body must respond to physical activities, external temperature, and other factors by homeostatically adjusting its blood flow to deliver nutrients such as oxygen and glucose to stressed tissues and allow them to function. Haemodynamic response (HR) allows the rapid delivery of blood to active neuronal tissues. Since higher processes in the brain occur almost constantly, cerebral blood flow is essential for the maintenance of neurons, astrocytes, and other cells of the brain.