Animal models of congenital hypoalgesia: Untapped potential for assessing pain-related plasticity.

Over the last 20 years a large number of transgenic mouse models have been produced showing different degrees of congenital hypoalgesia; some of these models mimic known human conditions while others seemingly have no human counterpart. However, very little significant contributions to our understanding of pain neurobiology were obtained from this multitude of animal models; in most cases the study of these animals was limited to the characterization of its pain perception without addressing the long term consequences of their hypoalgesic condition. In this review we discuss the untapped potential that these animal models of congenital hypoalgesia hold for future studies addressing brain plasticity during permanent conditions of reduced pain perception, and that may result in important insights on the interplay between pain, emotion, and cognition. Revisiting hypoalgesia using modern techniques of functional neurophysiology in awake animals may complement the recent literature of functional clinical and preclinical studies that improve our understanding of the central malplasticity caused by pain.