title: When the sun prickles your nose: an EEG study identifying neural bases of photic sneezing.
abstract: BACKGROUND
  Exposure to bright light such as sunlight elicits a sneeze or prickling sensation in about one of every four individuals. This study presents the first scientific examination of this phenomenon, called 'the photic sneeze reflex'.
  
  
  RESULTS
  In the present experiment, 'photic sneezers' and controls were exposed to a standard checkerboard stimulus (block 1) and bright flashing lights (block 2) while their EEG (electro-encephalogram) was recorded. Remarkably, we found a generally enhanced excitability of the visual cortex (mainly in the cuneus) to visual stimuli in 'photic sneezers' compared with control subjects. In addition, a stronger prickling sensation in the nose of photic sneezers was found to be associated with activation in the insula and stronger activation in the secondary somatosensory cortex.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Psychological Institute, Division of Neuropsychology, University of Zurich, Zurich, Switzerland. n.langer@psychologie.uzh.ch
authors.forename: Nicolas
authors.initials: N
authors.lastname: Langer
authors.forename: Gian
authors.initials: G
authors.lastname: Beeli
authors.forename: Lutz
authors.initials: L
authors.lastname: Jäncke
mesh_terms: D000328:Adult; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D009666:Nose / Q000502:physiology; D010775:Photic Stimulation; D012018:Reflex / Q000502:physiology; D012912:Sneezing / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D013472:Sunlight; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult