Pain receptors are not present in brain neural tissue but are associated with blood vessels and meninges, and increased blood pressure to the brain can activate these receptors, potentially causing headaches.

“We don't have pain receptors in the neural tissue in the brain. We have them in the meninges and predominantly associated with the blood vessels, the walls of the blood vessels. So if you have something which will dramatically increase your blood pressure going to the brain, you're likely to get...”