1. Headache Group; Institute of Psychiatry, Psychology and Neuroscience, King's College; London UK
2. Neuroscience Unit; Conci Carpinella Institute; Córdoba Argentina
3. Biomedical Physics Department; National University of Córdoba; Córdoba Argentina
4. Neurologia; Hospital das Clínicas da Faculdade de Medicina, Universidade de São Paulo; Sao Paulo Brazil
5. Anesthesiology Department; Sanatorio Allende; Córdoba Argentina
6. University of the West of England; London UK