All animal procedures presented in this paper followed the University of Washington Institutional Animal Care and Use Committee guidelines. Surgical preparation for in vivo voltammetry used aseptic technique. Male rats weighing between 300g and 350g (Charles River, CA) were anesthetized with isoflurane and placed in a stereotaxic frame. The scalp was swabbed with 10% povidone iodine, bathed with a mixture of lidocaine (0.5 mg/kg) and bupivicaine (0.5 mg/kg), and incised to expose the cranium. Holes were drilled and cleared of dura mater above the nucleus accumbens core (1.3-mm lateral and 1.3-mm rostral from bregma), the dorsolateral striatum (4.3-mm lateral and 1.2-mm rostral from bregma), and/or the nucleus accumbens shell (0.8-mm lateral and 1.2-mm rostral from bregma) for microsensors, above the midbrain (1.0-mm lateral and 5.2-mm caudal from bregma) for a stimulating electrode in some animals, and at convenient locations for a reference electrode and three anchor screws. The reference electrode and anchor screws were positioned and secured with cranioplastic cement, leaving the stimulating electrode and working electrode holes exposed. The microsensors were then attached to the voltammetric amplifier and lowered into the target recording regions (7.0-mm ventral of dura mater for nucleus accumbens, 4.0-mm ventral of dura mater for dorsolateral striatum). For animals in which a stimulating electrode was implanted, the voltammetric waveform was applied at 10 Hz and dopamine monitored. Next, the stimulating electrode (Plastics One, VA) was lowered 7.0 mm below dura mater and electrical stimulation (60 biphasic pulses, 60 Hz, ±120 µA, 2 ms/phase) was applied via an optically isolated, constant-current stimulator (A-M Systems, WA). If an evoked change in dopamine concentration was not observed at the working electrode, the stimulating electrode was positioned 0.2 mm more ventral. This was repeated until dopamine efflux was detected following stimulation. It was then lowered further in 0.1-mm increments until dopamine release was maximal. This is usually when the stimulating electrode is 8.4-mm ventral from dura mater. Finally, cranioplastic cement was applied to the part of the cranium that is still exposed to secure the stimulating electrode and microsensor(s).