Left panels: mean cerebral perfusion at rest under (a) isoflurane, (b) medetomidine or (c) etomidate anesthesia. Numbers in the bars reflect sample sizes, error bars indicate standard deviations. Right panels: time course of perfusion response in whole brain and the PFC before and after injection of acetazolamide as a proxy for cerebrovascular reserve capacity. Responses are presented as percentage change relative to baseline (black dashed line at 100%) to allow comparison of different regions of interest. The left border of the gray-shaded area designates the time-point of acetazolamide application. Acetazolamide (30 mg/kg) was injected intravenously in isoflurane- and medetomidine-anesthetized animals and intraperitoneally under etomidate, thus explaining the slightly delayed response onset for the latter. Data are shown as sample means, and error bars represent 95% confidence intervals to visualize significant deviations from baseline. Sample sizes are provided below each graph. Color-coded magnetic resonance images represent the percentage change of perfusion (according to the color bar along the y axis) as an average over three consecutive time-points for a representative coronal plane (rats: +1.00 mm; mice: +1.34 mm relative to bregma). PFC, prefrontal cortex; SD, Sprague Dawley.