Neurons, like all other cells, require energy to function. This energy is supplied in the form of glucose and oxygen (the oxygen being carried in haemoglobin). The blood supply of the brain is dynamically regulated to give active neural assemblies more energy whilst inactive assemblies receive less energy.
The molecular biology of haemodynamic regulation
The precise mechanism behind neurovascular coupling is currently under active research and furious debate, but roughly the following model has gained consensus:
- Active excitatory neurons release the neurotransmitter glutamate
- Glutamate opens NMDA receptors on other neurons which allows calcium ions into the neuron
- Glutamate also binds to the metabotropic glutamate receptor on astrocytes
- Siesjo, Bo K. (1978). Brain Energy Metabolism. New York: Wiley. p. 612. 0 471 99515 0.
- Stefanovic, Bojano J. (2007). "Functional uncoupling of hemodynamic from neuronal response by inhibition of neuronal nitric oxide synthase". Journal of Cerebral Blood Flow & Metabolism. 27: 741–754. doi:10.1038/sj.jcbfm.9600377. Retrieved 2007-05-22. Unknown parameter
- Rossi, David J (2006). "Another BOLD role for astrocytes: coupling blood flow to neural activity". Nature Neuroscience. 9: 159–161. doi:10.1038/nn0206-159. Retrieved 2007-05-22.