1) Natalizumab-associated PML and 2) Topic of the month: Preventive neurology. This podcast for the Neurology Journal begins and closes with Dr. Robert Gross, Editor-in-Chief, briefly discussing highlighted articles from the print issue of Neurology. In the second segment Dr. Alex Bragg interviews Dr. Avindra Nath about his paper on natalizumab-associated PML. In the next segment, Dr. Stacey Clardy is reading our e-Pearl of the week about Eagle syndrome. In the next part of the podcast Dr. Matt Barrett interviews Dr. Paula Rackoff on patients' steroids and prevention of osteoporosis. Over the subsequent two weeks, Ted Burns will interview GianPietro Sechi and David Saperstein on B vitamin deficiencies. The participants had nothing to disclose except Drs. Nath and Clardy.Dr. Nath serves on scientific advisory boards for Biogen Idec and DioGenix, Inc.; serves as an Associate Editor for the Journal of Neurovirology; may accrue revenue on patents re: Tat as an immunogen, Diosgenin for Treatment of Neurodegenerative Diseases, Role of Kv Channels in Neuroregeneration and Protection, Role of Lominoid compounds as neuroprotective agents, and Tat ELISA; has served as a consultant for Nerveda Inc. and Elan Corporation; receives research support from the NIH; and has served as an expert advice in medico-legal cases.Dr. Clardy serves on the editorial team for the Neurology® Resident and Fellow Section.