Figure 1. phMRI of Yohimbine.
Top: Yohimbine Infusion Procedure. Following a 5 min baseline, yohimbine was infused in four separate infusions, each infusion lasting 20 sec, and with an interinfusion interval of 2 min, as shown in the box (see Text). Middle: Plasma levels of Yohimbine. Based on prior reports [77] doses of yohimbine reach maximal levels immediately after intravenous infusion and remain high for at least 20 min. Bottom: Plasma levels of norepinephrine rapidly follow yohimbine infusions [78]. These levels also remain high for the duration of the phMRI data acquisition.