Following extraction, [DA] was averaged into 1 s bins across a 20 s time window (10 s before and 10 s following the cocaine-reinforced lever press response). All data sets were tested for normality using D’Agostino & Pearson omnibus normality test, prior to ANOVA or t-test analysis. One-way repeated measures ANOVAs were performed on [DA] across the 20 s window, followed by Dunnett’s test comparing [DA] within each 1 s bin to baseline (defined as dopamine concentration within 10 to 9 s before the response). T-test analysis was used to compare stimulated [DA] at phasic versus nonphasic cell firing locations across the core and shell. Signal-to-baseline (S:B) ratios for dopamine were determined by dividing the mean [DA] during the period of peak changes (1 s of peak increases within 0.6 s before to 2 s following the response, i.e., the signal) by the mean [DA] during a baseline period.
