Endogenous and exogenous modulators of potentials evoked by a painful cutaneous laser (LEPs)

S. Ohara, W. S. Anderson, H. C. Lawson, H. T. Lee, F. A. Lenz

Research output: Chapter in Book/Report/Conference proceedingChapter


Little is known about the specific functions of the human cortical structures receiving nociceptive input, their relationship to various dimensions of pain, and the modulation of these inputs by attention. We now review studies demonstrating the subdural potentials evoked by a cutaneous laser stimulus which produces a pure pain sensation by selective activation of cutaneous nociceptors (LEPs). These LEPs were localized over human anterior and middle cingulate (A & MCC), somatosensory (SI) and parasylvian (PS) cortices. LEP, lesion and imaging data define pain-related elements within each of these structures: insula and parietal operculum within PS, anterior and middle cingulate cortex, and possibly Brodman's areas 3a, 3b and 1 within SI. LEPs recorded over each of these areas is modulated with laser intensity and evoked pain. Attention to the painful laser produces an increase in the amplitude of LEPs over all three cortical areas and emergence of a late positive potential over ACC alone. These studies provide clear evidence of human cortical structures receiving nociceptive input and the modulation of that input by exogenous (e.g. laser intensity) and endogenous factors (e.g. directed attention).

Original languageEnglish (US)
Title of host publicationActa Neurochirurgica, Supplementum
Number of pages3
StatePublished - 2006

Publication series

NameActa Neurochirurgica, Supplementum
ISSN (Print)00651419


  • anterior cingulated
  • Human pain
  • insula
  • parietal operculum
  • primary somatic sensory cortex
  • secondary somatic sensory cortex
  • ventral posterior thalamus

ASJC Scopus subject areas

  • Clinical Neurology
  • Surgery
  • Medicine(all)


Dive into the research topics of 'Endogenous and exogenous modulators of potentials evoked by a painful cutaneous laser (LEPs)'. Together they form a unique fingerprint.

Cite this