Photic sneeze reflex

The photic sneeze reflex ( from Greek: φῶς Phos gene φωτός photos " light." ) Describes the phenomenon that some people sneeze when they are exposed to sudden brightness ( eg, sunlight ).

Dissemination

In varying degrees observed 17 to 35 percent of people with you this effect. Among those affected women are slightly overrepresented. There is a statistically significant correlation between the occurrence of the photic Niesreflexes and the presence of a deviated septum. The vast majority of those affected will react with a maximum of three times sneezing within a period of 20 seconds.

Causes

The causes are not fully understood. As very probably true, however, an autosomal dominant inheritance, so one speaks also of ACHOO syndrome ( Autosomal Dominant Compelling Helio- Ophthalmic Outburst of Sneezing ). The most common theory is that these people of the optic nerve runs ( optic nerve ) unusually close to the trigeminal ( trigeminal nerve ). The latter is responsible for nerve sensory innervation of the face and the nasal mucosa. Will now run a lot of action potentials along the optic nerve in sudden brightness, Drilling nerve is stimulated electrically, which is processed by the brain as an irritation of the nasal mucosa and thus is expressed as sneezing. If the eye becomes accustomed to the brightness, so the pupils are constricted and the sensitivity of the retina has detached, leaves after sneezing.

The photic sneeze reflex has been identified as a risk factor for military pilots, as they thereby possibly could be deflected in a critical flight situation of control of their machine. In similar experiments, it was found that the interference filter and thus sunglasses offer no protection against the sneeze reflex. It is therefore considered that not the wavelength, but the intensity of light is responsible for the attraction.

Early attempts to explain

Probably the first records for this phenomenon can be found in Pseudo- Aristotle. The author does not cause sneezing back to the light, but on the heat effect of the sun. Instead of a photic one would speak of a thermal sneeze reflex.

"Why do you sneeze more easily if you look at the sun? But probably because it sets (the sun) by heating ( sneezing ) in motion, as when one touches with feathers ( the nose). Because in both cases, you do the same: by produced by the movement of heat, you turn the moisture faster air. The discharge of these air but is sneezing. "

" Why only occurs sneezing with us not sleep, but instead it were entirely in the Guards? But probably because sneezing [ also ] comes about through a certain warmth that sets the body in motion, from the proceeds ( sneezing ). Therefore we are ready against the sun, if we want to sneeze while, when we sleep, the heat is crowded inside. "

Nearly 2,000 years later, the English philosopher and statesman Francis Bacon contradicts this view. In Sylva Sylvarum or A Naturall History in Ten Centuries ( 1626 ), a posthumous compilation of descriptions of nature, he believes that the sneezing not proceeded from the heating of the nose. The reason lies rather in the fact that liquid flowed from the brain to the eyes, and from there into the nose. The exact cause of this outflow of cerebrospinal fluid Bacon is silent, however. Whether he turns out the light or the heat responsible must remain open. ( Due to its determination that the sneezing not proceeded from the heating of the nose, Bacon includes a thermal effect is not generally the cause of sneezing from. )

"Looking against the sun doth induce sneezing. The cause is not the heating of the nostrils, for then the holding up of the nostrils against the sun, though one wink, would do it; but the drawing down of the moisture of the brain; for it will make the eyes run with water: and the drawing of moisture to the eyes, doth draw it to the nostrils by motion of consent; and as followeth sneezing: as contrariwise, the tickling of the nostrils within, doth draw the moisture to the nostrils, and to the eyes by consent; They also want for water. But yet it hath been -observed, if one did be about to sneeze, the rubbing of the eyes till they run with water will preventDefault it. Whereof the cause is, for the humor did Which was descending to the nostrils, is diverted to the eyes. "

" Look into the sun causes sneezing. The reason for this lies not in the heating of the nostrils - for it is sufficient if one stretches out the nostrils for a moment the sun - but in the pulling down of the fluid of the brain. Because it makes the eyes watery and the drawing down of the liquid to the eyes she pulls in the same movement to the nostrils and it follows sneezing. As vice versa in the nostrils draws the liquid tickling the nostrils and in the match to the eyes, because they are watery. It was observed, however, that if one is in the act of sneezing until they run rubbing the eyes with water, prevents this. The reason of this is that the liquid descending to the nostrils, is redirected to the eyes. "

Mentions in Fiction

Also found in the photic sneeze reflex Fiction of repeatedly input.

Georg Buchner mentions him in 1836 authored drama Woyzeck:

" DOCTOR: ... I 've seen seen with these eyes; I plugged ' grade nose out the window and let fall into the sun's rays to observe the sneezing. "

Another body found in Ivan Sergeyevich Turgenews 1862 erschienenem novel Fathers and Sons. In one scene of the novel, the two main characters Yevgeny Bazarov and lie sprawled in the hay. A staff doctor comes in and says:

" ... You have chosen a delicious cookies and give yourselves an excellent job. On the ' earth ' are, in the look ' sky ' ... You know - this has a deeper meaning! Bazarov who feels disturbed by the appearance of the medical officer, responds: I look only to the sky, if I want to sneeze. "

1868 was the photic sneeze reflex input in Wilhelm Busch's short story in pictures The pinch. A man who has taken a pinch of snuff, try out different things, so the itching in the nose actually leads to liberating sneezing. A look at the sun finally brings salvation.

"And all this does not help, / So, a look into the sunlight. "

Also be found in recent literature mentions:

"But I could see that he curiously left and right perceived his environment that he at this moment - as he went -. Stared with open eyes at the sun until he had to sneeze "