1. Department of Physiology, Faculty of Medicine, UNAM, P.O. Box: 70-250, Mexico City, Mexico
2. Department of Physiology, School of Medicine, National Autonomous University of Mexico; Mexico City, Mexico
3. Coordination of Psychobiology, School of Psychology, National Autonomous University of Mexico, Mexico City, Mexico
4. Department of Physiology, Faculty of Medicine, UNAM, P.O. Box: 70-250, Mexico City