Photic sneeze reflex is a condition triggered by exposure to bright light.
Sneezing can’t really be controlled – it’s one of the body’s reflexes, and is typically associated with irritation in the nose. From here the signal is sent via neural pathways to the brain, resulting in a powerful release of air through your mouth and nose, which not only helps expel mucous or irritants from the nasal passages as fast as possible, but also contracts a bunch of muscles in the body, including the eyelids and the trachea.
The photic sneeze reflex appears to be the result of crossed wires somewhere along the trigeminal nerve. Also known as the fifth cranial nerve, it’s the largest and most complex paired nerve in the head, with three major branches leading to the eyes, nasal cavity, and the jaw. It’s a crowded place in terms of nervous signaling, so it’s not surprising that the trigeminal nerve would occasionally get the reflexes wrong. Bright light causes your pupils to contract, so that signal might be mistakenly sent to the nose as well.
Another nervous system-related hypothesis states that these sun-related sneezes might occur thanks to “parasympathetic generalization”, a process that occurs when one part of the parasympathetic nervous system – such as the pupil of the eye – is excited by a stimulus and happens to activate other parts of the system as well – such as the membranes in the nose.
The next time you head outside on a sunny day, see if you let out a sneeze or series of sneezes. Your reaction might be due to allergies, or it might be the change in light. If you have the reflex, you probably inherited the trait from a parent.Leave a reply