Single-trial detection of human brain responses evoked by laser activation of Adelta-nociceptors using the wavelet transform of EEG epochs

Neurosci Lett. 2004 May 6;361(1-3):241-4. doi: 10.1016/j.neulet.2003.12.110.

Abstract

The aim of this study was to identify EEG changes induced by Adelta-nociceptor activation in single trials. In a preliminary experiment, intense CO(2) laser stimuli were delivered to the hand dorsum of five volunteers. The average amplitude of EEG epochs was estimated in the time-frequency (TF) domain using the continuous Morlet wavelet transform (CMT). The result was used as a TF filter enhancing Adelta-nociceptor induced EEG responses. In a second experiment, eight other subjects were delivered laser stimuli with six intensities. The CMT of each EEG epoch was computed. After applying the TF filter, amplitudes within a predefined interval were summed. Whether this sum predicted the occurrence of Adelta-nociceptor activation was tested using the reaction-time to discriminate between Adelta- or C-fibre mediated detection. Results showed that this method accurately identified single-trial EEG responses to Adelta-nociceptor activation.

MeSH terms

  • Adult
  • Afferent Pathways / physiology*
  • Afferent Pathways / radiation effects
  • Cerebral Cortex / physiology*
  • Dose-Response Relationship, Radiation
  • Electroencephalography / methods
  • Evoked Potentials / physiology*
  • Fourier Analysis
  • Hot Temperature / adverse effects
  • Humans
  • Lasers
  • Nerve Fibers, Myelinated / physiology*
  • Nerve Fibers, Myelinated / radiation effects
  • Nerve Fibers, Unmyelinated / physiology
  • Nerve Fibers, Unmyelinated / radiation effects
  • Nociceptors / physiology*
  • Nociceptors / radiation effects
  • Pain / physiopathology*
  • Reaction Time / physiology
  • Reaction Time / radiation effects