Attention-related modifications of ultra-late CO2 laser evoked potentials to human trigeminal nerve stimulation

Massimiliano Valeriani, Domenico Restuccia, Domenica Le Pera, Liala De Armas, Toni Maiese, Pietro Tonali

Research output: Contribution to journalArticlepeer-review


Our study aimed at investigating the scalp topography of ultra-late CO2 laser evoked potentials (LEPs), which are related to C fiber activation, and at exploring the effect of attention deviation on ultra-late LEPs. Brain responses to non-painful CO2 laser stimuli were recorded in ten healthy subjects in three different conditions: (i) neutral condition in which subjects did not have any task; (ii) distraction condition in which subjects were asked to perform a mathematical task; and (iii) attention condition in which subjects had to count the number of stimuli. In all subjects, also Ao fiber-related late LEPs were recorded after painful CO2 laser stimulation. The ultra-late LEPs in attention condition included an earlier negative potential (ultra-late N1) in the contralateral temporal region and a simultaneous frontal positive response (ultra-late P1). Later, a vertex biphasic component (ultra-late N2a and ultra-late P2) was identifiable. The vertex ultra-late LEP amplitude was significantly decreased in both neutral and distraction condition. Ultra-late LEPs showed a longer latency than late LEPs, but the scalp distributions of both ultra-late and late LEPs were very similar, thus suggesting that the same cerebral areas may be involved in their generation. Since attention deviations have a strong effect on ultra-late LEP amplitude, the subject's attention should be addressed to CO2 laser stimuli when ultra-late LEPs are used for clinical purposes.

Original languageEnglish
Pages (from-to)329-333
Number of pages5
JournalNeuroscience Letters
Issue number3
Publication statusPublished - Sep 6 2002


  • Attention
  • C fibers
  • CO laser
  • Evoked potentials
  • Human brain

ASJC Scopus subject areas

  • Neuroscience(all)


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