Fig. 1. (  A ) Absolute values of regional cerebral metabolic rate of glucose (rcMRGlu) in the awake condition and during general anesthesia with 1 minimum alveolar concentration xenon.  (B ) rcMRGlu in the awake condition and during sedation with subanesthetic concentrations of propofol (target concentration level < 1.0 μg/ml). For comparison, values of global MRGlu are in addition shown. Data are presented as mean ± SD. **P < 0.01 , ***P < 0.005, ****P < 0.0001, drug  versus awake. †P < 0.05, ‡P < 0.005, xenon  versus propofol.