title: Role of explicit verbal information in conditioned analgesia.
abstract: BACKGROUND
  The exact role of expectation in conditioned analgesia is still elusive as it is not clear whether conditioning is an automatic process or rather it is cognitively mediated. This study is aimed at understanding the role of explicit verbal information in conditioned analgesia.
  
  
  METHODS
  Two groups of healthy subjects received a conditioning procedure whereby two visual cues were paired with increase and decrease in stimulus intensity. In the 'conditioning/verbal information' group (VER), subjects were informed about the meaning of the cues, whereas no information was given to the second group (noVER). After two conditioning blocks, an evocation session was run in which the stimulus intensity was the same, irrespective of the cues. Pain perception was assessed according to a numerical rating scale from 0 (no pain) to 10 (maximal pain). The N2-P2 component of laser-evoked potentials (LEP) was used as an index of index of brain responses to nociceptive stimuli.
  
  
  RESULTS
  In the evocation session, only the VER group reported a decrease in pain rating and LEP amplitude when the cues were presented, suggesting that the visual-analgesic association does not occur without explicit verbal information.
  
  
  CONCLUSIONS
  In line with the cognitive theory of conditioning, our results indicate that just pairing a cue with different pain stimulus intensities is not sufficient, per se, to produce a learning process. What matters is the informational cognitive content of the cue, i.e. the meaning assigned to the cue itself. These findings may help understand the mechanisms of conditioned analgesia and more in general of learning.
authors.affiliation: Department of Neuroscience, University of Turin Medical School, Italy; National Institute of Neuroscience, Turin, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Carlino
authors.forename: D M E
authors.initials: DM
authors.lastname: Torta
authors.forename: A
authors.initials: A
authors.lastname: Piedimonte
authors.forename: E
authors.initials: E
authors.lastname: Frisaldi
authors.forename: S
authors.initials: S
authors.lastname: Vighetti
authors.forename: F
authors.initials: F
authors.lastname: Benedetti
mesh_terms: D000328:Adult; D000698:Analgesia / Q000379:methods; D000700:Analgesics / Q000627:therapeutic use*; D001921:Brain / Q000187:drug effects; D003213:Conditioning, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D066331:Laser-Evoked Potentials / Q000187:drug effects; D008297:Male; D010146:Pain / Q000523:psychology*; D059408:Pain Management; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D015990:Placebo Effect; D013060:Speech; D055815:Young Adult
chemical_list: D000700:Analgesics