CA transients in the mPFC of rats evoked by midbrain stimulation. (A) Representative current-versus-time traces and corresponding cyclic voltammograms detected in an individual rat. The current at the oxidation potential for CA is shown ±5s around the electrical stimulation (rectangle). The cyclic voltammogram indicates current at the full range of applied potentials measured at the peak of the CA release event. (B) The track of the bipolar stimulating electrode (dotted lines indicate the two wires) through the midbrain, axes in mm, adapted from (Paxinos and Watson, 1998). (C) Electrically-evoked CA release in the mPFC presented as function of midbrain stimulation site (n=5 rats). The evoked CA signals (Id) were normalized in each rat by dividing by maximal response observed in the rat (Idmax). * significantly different from −5.0 mm depth, p<0.05. Abbreviations: DNB, dorsal noradrenergic bundle; SN, substantia nigra; VNB, ventral noradrenergic bundle; VTA, ventral tegmental area.