1. Institute of Neuropathology, University Hospital RWTH Aachen, 52074 Aachen, Germany
2. EURON—European Graduate School of Neuroscience, Maastricht University, 6229 ER Maastricht, The Netherlands
3. Department of Ophthalmology, University Hospital RWTH Aachen, 52074 Aachen, Germany
4. Institute of Biological Information Processing, Molecular and Cellular Physiology, IBI-1, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
5. Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
6. Department of Neurology, Eleanor and Lou Gehrig ALS Center, Columbia University, New York, NY 10032, USA