1. Headache Research Unit, University Department of Neurology CHR, Citadelle Hospital, University of Liège, Liège, Belgium
2. IRCCS – Fondazione Bietti, Research Unit of Neurophysiology of Vision and Neurophthalmology, Rome, Italy
3. Department of Neurosurgery, University of Liège, Liège, Belgium
4. Department of Neuroanatomy, University of Liège, Liège, Belgium
5. Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Department of Neurology, Brussels, Belgium