Fidias Leon-Sarmiento. MD, PhD is a senior research investigator at the University of Pennsylvania's Perelman School of Medicine. He started this position after receiving training in movement disorders at the National Institutes of Health and obtaining a PhD in neurophysiology from Kagoshina University, Japan. Dr. Leon-Sarmiento has pioneered the use of transcranial magnetic stimulation (procedure that uses magnetic fields to stimulate nerve cells) and direct current stimulation to study sensory and motor changes that occur in Parkinson's disease. Much of his current research focuses on human corticospinal (brain system) physiology (function), particularly brainstem and spinal cord reflexes. He presently spearheads the Smell and Taste Center's efforts to determine the role of the brainstem in Alzheimer's and Parkinson's. He recently discovered that olfactory (sense of smell) dysfunction is an early indicator of myasthenia gravis and Chaga's disease, among others. He is the author or co-author of more than 200 peer-reviewed publications and has received numerous awards for his scientific achievements, including multiple awards from international institutions.