The influence of semantic priming on event-related potentials to painful laser-heat stimuli in humans.

In this study we investigated the effects of different semantic primes on the processing of painful stimuli. For prime stimuli, descriptors of three categories were used: somatosensory pain-related, affective pain-related, and neutral adjectives. While subjects (n=10) processed these primes, a painful laser-heat stimulus was applied. Laser-evoked potentials (LEPs) were recorded and pain intensity ratings were obtained after each single laser stimulus. Painful stimuli applied while subjects processed pain-related primes (affective and somatosensory adjectives) resulted in larger LEP amplitudes at 370 ms post laser stimulus compared to amplitudes of laser-evoked activities while subjects processed neutral primes (F((2,18))=3.90, P=0.05). It is suggested that pain-related semantic primes might preactivate neural networks subserving pain memory and pain processing. The processing of pain-related primes seems to preactivate cortical cell-assemblies involved in the processing of the succeeding painful laser stimuli.