Wednesday, February 24, 2010

Nothing To Sneeze At ... Unless It's Sunny

Apparently, exposure to sunlight can elicit a sneezing reaction in some people. A recent PLoS paper, by researchers at the University of Zurich, concludes:
We propose that the photic sneeze phenomenon might be the consequence of higher sensitivity to visual stimuli in the visual cortex and of co-activation of somatosensory areas. The ‘photic sneeze reflex’ is therefore not a classical reflex that occurs only at a brainstem or spinal cord level but, in stark contrast to many theories, involves also specific cortical areas.

Ah choo! (Please draw the curtains)


  1. I have known several people who did this. One colleague would regularly sneeze three times when walking outside. It became so commonplace, we ran out of jokes.

  2. How can they know? It is never sunny in Zurich.

  3. Deep. Photic sneezing only requires "sunlight," not sunny. The latter was pure poetic license, on my part, to hook readers. Both words worked. So, maybe the U of Z authors won't have to retract, after all.

  4. Great article. The following line of the article is intriguing:

    "Usually, photic sneezing is evoked by sunlight, but Sedan [4] argues that artificial light, such as the light of an ophthalmoscope, photographic flash, or ultraviolet light, should also cause a sneeze."

    So potentially taking a flash photo of a subject prone to photic sneezing in a darkened room would be enough to trigger a sneeze?

    I wonder if 10:06 anonymous above could track down said colleague for some experimentation...