Herpertz SC, et al. - In order to investigate if pain processing in humans is modulated by the neuropeptide oxytocin (OT), differentiation of behavioral and neuronal OT effects on pain perception and pain anticipation was done using a Pavlovian conditioning paradigm. Researchers administered intranasally OT to 46 males in a randomized double-blind, placebo-controlled group design. Perceived pain was not directly affected by OT, however, it led to modulation of blood-oxygen-level-dependent response in the ventral striatum for painful vs warm unconditioned stimuli (US) and lowered the activity in the anterior insula with repeated thermal pain stimuli. Via the ventral striatum and by inducing habituation in the anterior insula, OT seems directly affecting pain processing. In addition, by boostering associative learning in general and the neuronal conditioned fear of pain response in particular, pain anticipation seems directly affected by OT.