The headache from eating ice cream too fast is called sphenopalatine ganglioneuralgia.
Why it is true
Cold on the roof of the mouth makes blood vessels constrict and then quickly widen. Nerves in the area read this sudden change as pain in the forehead. Pressing your tongue against the roof of your mouth warms it and the pain fades in seconds.
Source: The FASEB Journal (Serrador et al., 2012)
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Related facts
The human brain itself has no pain receptors, which allows awake brain surgery to be performed without causing pain to the brain tissue.
The human brain has more connections than stars in the Milky Way.
The human brain stops growing in size around age 18, but continues to develop and mature until the mid-20s.
The human brain uses about 20% of the body's total energy.
