Fig. 2. Linear mixed-effects models for electrical, pressure, ice-water, heat, and ischemic pain. The linear population fit and individual post hoc  Bayesien predictions for the subjects of the alfentanil group are plotted together with the raw data of both the alfentanil and the placebo groups. The tolerated stimulation intensity represent the measured effect in electrical, pressure, and heat pain and the area under the pain intensity (visual analog scale)–time curve (AUC) in ice water and ischemic pain. Filled circles = raw data, alfentanil group; open circles = raw data, placebo group; thin lines = Bayesien predictions of the effect for every subject in the alfentanil group; thick solid line = population-fit drug group; thick dashed line = population-fit placebo group.