The quest to acquire knowledge and understanding of pain has had crucial moments in which the evolution of the process has been dramatically changed. These moments have been revelations that have opened the path to rethinking previously accepted knowledge and created new horizons of research, understanding and treatment. When Melzack and Wall first described what would come to be known as the "Gate Control theory" they were able not only to clarify basic aspects of pain development but to lead the way to further basic and clinical research studies. They psychological aspects, the clinical basis and the structural anatomical and physiological components created one of the most complete theories in medical sciences and the ground for the basi...