Distraction affects frontal alpha rhythms related to expectancy of pain: an EEG study

Neuroimage. 2006 Jul 1;31(3):1268-77. doi: 10.1016/j.neuroimage.2006.01.013. Epub 2006 Mar 10.

Abstract

Previous electroencephalographic (EEG) evidence has shown event-related desynchronization (ERD) of alpha rhythms before predictable painful stimuli, as a possible neural concomitant of attentional preparatory processes (Babiloni, C., Brancucci, A., Babiloni, F., Capotosto, P., Carducci, F., Cincotti, F., Arendt-Nielsen, L., Chen, A.C., Rossini, P.M., 2003. Anticipatory cortical responses during the expectancy of a predictable painful stimulation. A high-resolution electroencephalography study. Eur. J. Neurosci. 18 (6) 1692-700). This study tested the hypothesis that alpha ERD before predictable painful stimuli is reduced as an effect of distraction. A visual warning stimulus preceded a laser painful stimulation, which was strictly followed by visual imperative stimuli. In the Pain (control) condition, no task was required after the imperative stimuli. In the Pain + Movement condition, subjects had to perform a movement of the right index finger. In the Pain + Cognition condition, they had to mentally perform an arithmetical task. EEG data were recorded in 10 subjects from 30 electrodes. Artifact-free recordings were spatially enhanced by surface Laplacian transformation. Alpha ERD was computed at three alpha sub-bands according to subjects' individual alpha frequency peak (i.e., about 6-8 Hz, 8-10 Hz, 10-12 Hz). Compared to the control condition, the subjects reported a significantly lower stimulus intensity perception and unpleasantness in the Pain + Movement and Pain + Cognition conditions. In addition, there was a cancellation of the alpha 3 ERD (i.e., about 10-12 Hz) in Pain + Cognition condition and even a generation of a statistically significant alpha 3 ERS in Pain + Movement condition. These effects were maximum over fronto-central midline. These results suggest that distraction during the expectancy of pain is related to a reduced neural desynchronization of fronto-central midline alpha rhythms (i.e., reduced cortical activation) towards an overt hyper-synchronization (cortical idling).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alpha Rhythm*
  • Attention / physiology*
  • Awareness / physiology
  • Brain Mapping
  • Cerebral Cortex / physiopathology*
  • Cortical Synchronization
  • Electroencephalography*
  • Female
  • Frontal Lobe / physiopathology*
  • Humans
  • Image Processing, Computer-Assisted*
  • Imaging, Three-Dimensional*
  • Magnetic Resonance Imaging*
  • Male
  • Motor Activity / physiology*
  • Motor Cortex / physiopathology
  • Pain / physiopathology*
  • Pain Measurement
  • Pain Threshold / physiology
  • Problem Solving / physiology*
  • Set, Psychology*
  • Signal Processing, Computer-Assisted*
  • Somatosensory Cortex / physiopathology