half of total stimulated release) revealed significant differences between the core (1315 ± 85 ms) and shell (1546 ± 75 ms) (t73 = 2.06, p < 0.05). Importantly, the differences in stimulated dopamine release peak concentrations and reuptake values across the core and shell could not be attributed to dissimilarities in electrode sensitivity. Specifically, carbon-fiber electrodes post-calibrated for [DA] in vitro in a flow injection system showed similar calibration factors regardless of whether measurements were made at nonphasic (7.55 ± 0.56 nA/μM) or phasic (7.78 ± 0.65 nA/μM) locations. Furthermore, there were a number of instances (n = 10) in which both nonphasic and phasic cells were recorded from the same electrode within a single electrode track.
