Why Do Some People Sneeze When They Look at the Sun? The Photics Sneeze Reflex
Did it ever happened to you, when you go out into the daylight after being in a dark room and you suddenly start sneezing? If yes, then you are one of the 30% of people on the earth who have the photic sneeze reflex.
One of the first ones who have started to research this reflex was Aristotle who was also suffering from this “problem”. His assumption was based on formation of moisture caused by sunlight, so the process of sneezing was triggered to get rid of excessive moisture in our organism. But later in 17th century Francis Bacon has proved that Aristotle was wrong.
In 1964 one study somehow clarified the “photic sneeze reflex”. Actually, this study showed that this symptom is autosomal dominant, it means that the cause of this reflex is only one gene. So, if one of your parents has such phenomenon, there is a 50 % probability that you will also have such reflex.
In 2010 Nicolas Langer wanted to find out the truth about the “photic sneeze reflex”, so he did it by observing the human brain. After multiple scans of different human brains he came to a conclusion. His first theory is that people with this reflex have more sensitive part of the brain which is responsible for visual perception. Excessive light irritation returns some reactions of other parts of human brain, including somatosensory system and the result is that we sneeze. In his second theory he partly agrees with Aristotle, but the reaction is caused not by the excessive moisture. The trigeminal nerve is close to the optic, so by suddenly irritating retina, the optic nerve sends some signals to our brain. Nicolas Langer assumes that some signals that brain receives are wrongly recognized, so the brain thinks that the signal comes from the trigeminal nerve which tells about some irritation in the nose, so we sneeze.