Spatial summation of heat induced pain within and between dermatomes

Somatosens Mot Res. 1997;14(2):119-25. doi: 10.1080/08990229771123.


The aim was to study spatial summation within and between ipsi- and contralateral dermatomes at different painful temperatures. For heat stimulation we used a computer controlled thermofoil based thermode. The thermode area could be varied in five discrete steps from 3.14 to 15.70 cm2. When we applied the stimuli within a dermatome, the mean heat pain threshold decreased significantly from 45.6 to 43.5 degrees C as the area was increased from minimum (3.14 cm2) to maximum (15.70 cm2). When the areas were increased involving different dermatomes (both ipsi- or contralateral), we found similar decreases in pain threshold. Spatial summation was also found within and between dermatomes at supra-threshold temperatures (46, 48, 50 degrees C). The study shows that spatial summation of pain is most likely a mechanism acting across segments and is existing from pain threshold to tolerance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Afferent Pathways / physiology
  • Functional Laterality / physiology
  • Humans
  • Male
  • Nociceptors / physiology*
  • Pain Measurement
  • Pain Threshold / physiology*
  • Recruitment, Neurophysiological / physiology*
  • Sensory Thresholds / physiology
  • Skin / innervation*
  • Thermoreceptors / physiology*
  • Thermosensing / physiology*