Fig. 1

Respiratory response to hypoxic stimulus before (grey bar) and 14 days (black bar) after ICV injection of vehicle (sham) or 6-OHDA. a Tidal volume; b frequency of breathing; c minute ventilation. N normoxia, H hypoxia, R recovery after the hypoxic stimulus. All values are mean ± SEM. *^#p < 0.05; ^##p < 0.01. *—statistical significance versus the respective normoxic baseline value (N), #—statistical significance versus the corresponding pre-injection with 6-OHDA value (n = 7–9 per group)