Fig. 1: Differential conditioning paradigm.
From: Acquisition learning is stronger for aversive than appetitive events
A pain intensity of about VAS 40 was induced by applying thermal heat stimuli to capsaicin-pretreated skin (tonic pain). An increase and decrease in temperature level led to pain exacerbation (VAS 80) and pain relief (VAS 0), respectively. The design consisted of habituation, acquisition, and extinction training. Assignment of geometric figures to experimental conditions was pseudo-randomized (example shown here).
