ClassX Video Lessons Why does sudden exposure to the sun cause sneezing? – Big Questions – (Ep. 216)
Have you ever stepped into bright sunlight and suddenly felt the urge to sneeze? This curious reaction is known as the photic sneeze reflex, or more scientifically, the autosomal dominant compelling helioophthalmic outburst. It’s a fascinating phenomenon that affects a significant number of people.
The photic sneeze reflex is a genetic trait that causes some people to sneeze when they are suddenly exposed to bright light, like sunlight. Studies suggest that between 10% and 35% of people experience this reflex. Interestingly, if you have this reflex, there’s a 50% chance that your children might inherit it too!
Scientists are still exploring why this reflex occurs, but there are a few popular theories. One theory dates back to the 1960s when psychiatrist Henry Everett proposed that mixed-up nerve signals in our nervous system might be responsible. Modern researchers have focused on two specific reflexes: the pupillary light reflex and the sneeze reflex.
This reflex is what makes our pupils shrink when we enter a bright area. The optic nerve, which controls the eyes, receives signals from the nervous system to adjust the pupil size.
The sneeze reflex is triggered when the trigeminal nerve in the brain senses an itch in the nose, causing us to sneeze. Normally, these two reflexes operate independently, but in people with the photic sneeze reflex, their pathways might overlap. This overlap is possible because the trigeminal nerve and the optic nerve are located close to each other.
Another idea is related to something called parasympathetic generalization. This occurs when the parasympathetic nervous system is stimulated, causing a widespread response in the body, which might include sneezing when exposed to light.
While the exact gene responsible for the photic sneeze reflex hasn’t been identified, researchers have noticed that the number of sneezes can be consistent within families. For example, if one family member sneezes three times when exposed to bright light, others might do the same.
Understanding the photic sneeze reflex is not just about satisfying curiosity. Some neurologists believe that studying this reflex could help us learn more about conditions like epilepsy and migraines, which can also be triggered by light.
So, the next time you find yourself sneezing in the sun, remember that it’s a unique trait shared by many and a subject of ongoing scientific research!
Step outside into bright sunlight and observe if you experience the photic sneeze reflex. Record your observations and compare them with your classmates. Discuss why some of you might sneeze while others don’t, and consider the genetic factors involved.
Conduct a survey with your family members to see if they experience the photic sneeze reflex. Create a chart to display your findings and analyze whether there is a pattern of inheritance in your family. Share your results with the class.
In groups, create a short skit that demonstrates how the pupillary light reflex and the sneeze reflex might overlap in people with the photic sneeze reflex. Use props and creativity to illustrate the interaction between the optic and trigeminal nerves.
Choose one of the theories explaining the photic sneeze reflex and research it further. Prepare a short presentation to explain the theory to your classmates, including any recent scientific findings or studies related to it.
Draw a comic strip that humorously depicts a day in the life of someone with the photic sneeze reflex. Highlight the situations where the reflex might occur and how the person deals with it. Share your comic with the class for a fun discussion.
Sure! Here’s a sanitized version of the transcript:
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Hi, I’m Craig, and this is Mental Floss video. Today, I’m going to answer AyanamiAIT’s big question: Why does sudden exposure to sunlight cause some people to sneeze? This phenomenon has a name: the photic sneeze reflex, or you can call it the autosomal dominant compelling helioophthalmic outburst.
According to various studies, between 10 and 35 percent of people have the photic sneeze reflex, and it’s actually genetic. One study from the 1960s revealed that if you have the photic sneeze reflex, there’s a 50% chance that your child will inherit it. There haven’t been too many studies on why it exists, though, and here comes the most common sentence in the big question: There are a few prevailing theories.
One theory came from a psychiatrist named Henry Everett in the 1960s. He suggested that the nervous system is to blame for sending signals that result in physical reflexes, and he believed that the photic sneeze reflex is an example of mixed-up nerve signals. Modern scientists have narrowed it down to two reflexes that may be the culprits: the pupillary light reflex and the sneeze reflex.
The pupillary light reflex is what causes our pupils to get smaller when we enter bright environments. A signal gets sent from the nervous system to the optic nerve, which controls the eyes. The sneeze reflex is what causes a sneeze when the trigeminal nerve in the brain detects an itch in the nose. Normally, these two reflexes are unrelated, but experts believe their paths may cross in people who have the photic sneeze reflex. This is possible because the trigeminal nerve and the optic nerve are close together.
Another theory is that it could be related to parasympathetic generalization, which occurs when the parasympathetic nervous system gets stimulated by something, causing the whole system to activate. This could potentially lead to light-induced sneezing.
As mentioned earlier, the photic sneeze reflex is genetic. Experts don’t know the specific gene that causes it, but interestingly, consistency between families has been observed. For instance, bright light might cause someone to sneeze just once, while others may experience three to five sneezes, and the number of sneezes tends to be similar within a family.
The reflex is still being researched because some neurologists believe it might provide insights into the causes of epilepsy and migraines, as those conditions are sometimes triggered by light as well.
Thanks for watching Mental Floss video! If you have a big question of your own that you’d like answered, leave it below in the comments. See you next week!
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Let me know if you need any further modifications!
Sneeze – A sudden, forceful, involuntary burst of air through the nose and mouth, often caused by irritation in the nasal passages. – When exposed to bright sunlight, some people may sneeze due to a reflex action.
Reflex – An automatic and rapid response to a stimulus that does not involve conscious thought. – The doctor tested my reflex by tapping my knee with a small hammer.
Genetic – Relating to genes or heredity, which are the biological instructions passed from parents to offspring. – Eye color is a genetic trait that is inherited from our parents.
Nervous – Relating to the system of nerves in the body that transmits signals between different parts of the body. – The nervous system is responsible for sending messages from the brain to the rest of the body.
Sunlight – The natural light coming from the sun, which is essential for the process of photosynthesis in plants. – Plants need sunlight to produce energy through photosynthesis.
Optic – Relating to the eye or vision. – The optic nerve is responsible for transmitting visual information from the eye to the brain.
Trigeminal – Relating to the trigeminal nerve, which is responsible for sensation in the face and motor functions such as biting and chewing. – The trigeminal nerve is one of the largest nerves in the head and plays a crucial role in facial sensation.
Pupils – The opening in the center of the eye that regulates the amount of light entering the eye. – When you enter a dark room, your pupils dilate to allow more light to enter the eye.
Parasympathetic – Relating to the part of the autonomic nervous system that conserves energy and slows down the heart rate. – The parasympathetic nervous system helps calm the body after a stressful event.
Research – The systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions. – Scientists conduct research to understand how genetic factors influence behavior.
