Dr. Carlos M. Contreras is a Senior Researcher at the Biomedical Research Institute, National Autonomous University of México (UNAM), Titular Professor of Experimental Clinical Medicine and Pharmacology at the Universidad Veracruzana, and member of the National Researchers System in México. Dr. Contreras is a medical Doctor and Doctor of Sciences at UNAM, were he has taught Physiological Psychology for the past three decades. His first studies at the Neurology and Neurosurgery Institute in México, involved the pharmacology of sleep, epilepsy, and drug dependence. He later received training in Biological Psychiatry in México and Experimental Psychology at the University of Wisconsin, Madison, USA. During the past 30 years, he has been studying and continuously publishing his results on the neurophysiology, neurochemistry, and ethology of affective disorders and anxiety and more recently the neurobiology of mother-infant linkage process.