趣談?dòng)⒄Z：大腦本身感受不到痛苦-Your Brain Feels No Pain
whine: to complain in a way that annoys others
receptor: a cell or nerve that responds to a sense
roof of one’s mouth: the palate; above the top of the tongue
contract: get smaller
overreact: to act as if a minor problem is a serious one
dilate: get wider
conserve: save
sensation: feeling
temples: two flat upper parts at the side of the forehead
Your Brain Feels No Pain
You can whine about an earache or a headache, but you can’t complain about pain in the brain. The human brain has no pain receptors. It can’t tell itself that it hurts. If the brain feels no pain, what is brain freeze? Brain freeze, also called an ice cream headache, occurs when you eat or drink something cold too quickly. When ice cream touches the roof of your mouth, the bloodvessels in your mouth contract. This sends a message to the brain about a change in your body heat. The brain overreacts and tries to conserve heat by contracting the blood vessels in your head. When the threat is over, the blood vessels in the head relax and dilate. This sends a quick rush of blood to the head. You feel this rush of blood as pain in your temples, face, or neck, but not in your brain. Try pressing your tongue against the roof of your mouth to relieve the sensation of brain freeze.
