1. Muscular Dystrophy Association/Amyotrophic Lateral Sclerosis Center, University of Washington Medical Center, Seattle, WA, USA,
2. Anatomy and Cell Biology and Center for Substance Abuse Research, Temple University, Philadelphia, PA, USA
3. Medical Scientist Training Program, School of Medicine, University of Washington, Seattle, WA, USA
4. Muscular Dystrophy Association/Amyotrophic Lateral Sclerosis Center, University of Washington Medical Center, Seattle, WA, USA, Neuromuscular Disease Division, Department of Neurology, University of Washington Medical Center, Seattle, WA, USA, Electrodiagnostic Laboratory, University of Washington Medical Center, Seattle, WA, USA