Christopher Bartley, physician psychiatrist at UCSF and neuroscientist
Originally Answered: If there are no pain receptors in the human brain then why do I get headaches?
There are different types of headaches but common headaches and migraines are thought to be due to inflammation or hyperactivity of the tissue surrounding the brain called the meninges. There are also pain receptors in head and neck muscles, skull, and along the cerebral blood vessels all of which may produce symptoms of a headache when activated. The brain itself does not have nociceptive receptors which is why brain surgery can be performed on awake patients as long as the overlying tissues are anesthetized.
Michael Soso, BA Berkeley Physiology/Biophysics 1967, PhD Neurophysiology UW 1975 and MD Stanford 1979, Neurology Residen…
Answered Oct 19 2016 · Upvoted by Jeffrey Schweitzer, Neurosurgeon
Originally Answered: If the brain can’t feel its own pain, what causes a headache?
Most of the answers properly point out that the head is full of stuff besides the brain and these tissues are full of nociceotors mediating pain.
Not mentioned is that the brain, while insensate, contains the mechanisms of sensation that interpret sensory organ input. In particular, the brain contains the pain system. For Migraine and some other pain syndromes, a critical part of the process is an alteration of the pain system itself. Simplistically, it’s as though the volume control of the pain system is turned to “11” and normally innocuous sensory input suddenly is rendered intolerable.
This explains why most headaches start without any injury and then disappear without leaving damage in their wake. The problem never was where the pain seemed to be located. Given the extreme pain a migraine can produce, it seems ridiculous that paralysis, blindness and dementia don’t regularly result from the intracranial violence involved. But it’s mostly an illusion, a hallucination of pain from a pain system out of control.
TL;DR: Headaches frequently involve derangement of the brain’s pain system which becomes inappropriately hyperactive.