Fig. 4. Blood oxygenation level-dependent (BOLD) signal intensity time courses (averaged across all subjects) depicting drug effects in the frontal, temporal, parietal, and occipital cortices and in the white matter and the cerebellum after bolus injection of 1 mg/kg esmolol over 2 min followed by infusion with 150 μg·kg−1·min−1for 2 min. The bolus injection period is indicated by the dark gray area , the subsequent infusion period by the light gray area . Injection of the esmolol bolus caused an immediate BOLD signal increase in all of the selected regions. Vertical lines represent SEM.