1. Neurosurgical Institute, University of Ioannina, 45500 Ioannina, Greece
2. Department of Anatomy Histology-Embryology, School of Medicine, University of Ioannina, 45500 Ioannina, Greece
3. Laboratory of Pharmacognosy, Faculty of Health Sciences, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
4. Department of Neurosurgery, University of Ioannina, 45500 Ioannina, Greece