Classical Conditioning Fails to Elicit Allodynia in an Experimental Study with Healthy Humans

Associative learning has been proposed as a mechanism behind the persistence of pain after tissue healing. The simultaneous occurrence of nociceptive and non-nociceptive input during acute injury mimics the pairings thought to drive classical conditioning effects. However, empirical evidence for classically conditioned allodynia is lacking. We aimed to manipulate pain thresholds with a classical conditioning procedure that used non-nociceptive somatosensory stimuli as conditioned stimuli (CS) and nociceptive stimuli as unconditioned stimuli. We also explored the influence of gender, depression, anxiety, negative affect, and pain catastrophizing on the main manipulation.